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<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note 1 - us-gaap:OrganizationConsolidationAndPresentationOfFinancialStatementsDisclosureTextBlock-->
<!-- xbrl,ns -->
<!-- xbrl,nx -->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left">
</div>
<div align="center" style="font-size: 10pt; margin-top: 0pt"><b>
</b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b>Note 1. Organization, Basis of Presentation, and Description of Business</b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt"><b><i>Organization</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Unless the context clearly indicates otherwise, references in this report to “we,” “our,” “us”
or similar language refer to Williams Partners L.P. and its subsidiaries.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     We are a publicly traded Delaware limited partnership. Williams Partners GP LLC, a Delaware
limited liability company wholly owned by The Williams Companies, Inc. (Williams), serves as our
general partner. As of March 31, 2011, Williams owns an approximate 73 percent limited partner
interest, a 2 percent general partner interest and incentive distribution rights (IDRs) in us. All
of our activities are conducted through Williams Partners Operating LLC (OLLC), an operating
limited liability company (wholly owned by us).
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The accompanying interim consolidated financial statements do not include all the notes in our
annual financial statements and, therefore, should be read in conjunction with the consolidated
financial statements and notes thereto for the year ended December 31, 2010 in our Annual report on
Form 10-K. The accompanying interim consolidated financial statements include all normal recurring
adjustments that, in the opinion of management, are necessary to present fairly our financial
position at March 31, 2011, results of operations for the three months ended March 31, 2011 and
2010, changes in equity for the three months ended March 31, 2011, and cash flows for the three
months ended March 31, 2011 and 2010.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The preparation of financial statements in conformity with accounting principles generally
accepted in the United States requires management to make estimates and assumptions that affect the
amounts reported in the consolidated financial statements and accompanying notes. Actual results
could differ from those estimates.
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b><i>Basis of Presentation</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     During fourth-quarter 2010, we closed the acquisition of a business represented by certain
gathering and processing assets in Colorado’s Piceance Basin from a subsidiary of Williams (the
Piceance Acquisition). As the acquired assets were purchased from a subsidiary of Williams, the
transaction was accounted for as a combination of entities under common control whereby the assets
and liabilities acquired are combined with ours at their historical amounts. The acquired assets
are reported in our Midstream Gas & Liquids (Midstream) segment, which includes a recast of the
statement of income for the prior period. The effect of recasting our financial statements to
account for this transaction increased net income by $9 million for the three months ended March
31, 2010. This acquisition does not impact historical earnings per unit as pre-acquisition
earnings were allocated to our general partner.
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b><i>Description of Business</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Our operations are located in the United States and are organized into the following reporting
segments: Gas Pipeline and Midstream.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Gas Pipeline is comprised primarily of the following interstate natural gas pipeline assets:
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>Transcontinental Gas Pipe Line Company, LLC (Transco), an interstate natural gas
pipeline extending from the Gulf of Mexico region to the northeastern United States;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>Northwest Pipeline GP (Northwest Pipeline), an interstate natural gas pipeline
extending from the San Juan basin in northwestern New Mexico and southwestern Colorado to
Oregon and Washington;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>A 24.5 percent equity interest in Gulfstream Natural Gas System L.L.C. (Gulfstream), an
interstate natural gas pipeline extending from the Mobile Bay area in Alabama to markets in
Florida.</td>
</tr>
</table>
</div>
<!-- Folio -->
<!-- /Folio -->
</div>
<!-- PAGEBREAK -->
<div style="font-family: 'Times New Roman',Times,serif">
<div style="margin-top: 0pt">
</div>
<div align="left" style="font-size: 10pt; margin-top: 0pt">
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Midstream is comprised primarily of the following natural gas gathering, processing and treating
facilities, oil gathering and transportation facilities and natural gas liquid (NGL)
transportation, fractionation and storage facilities and investments:
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>Two gathering systems and the Echo Springs and Opal processing plants serving the
Wamsutter and southwest areas of Wyoming;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>A gathering system, the Ignacio, Kutz and Lybrook processing plants and the Milagro and
Esperanza natural gas treating plants, all serving the San Juan basin in New Mexico and
Colorado;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>A gathering system, natural gas liquids pipeline and the Willow Creek and Parachute
processing plants in Colorado;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>An equity interest in Laurel Mountain Midstream, LLC, serving the Marcellus shale
region of western Pennsylvania;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>Gathering pipelines and compressor stations in the Appalachian basin of Pennsylvania;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>Onshore and offshore natural gas and oil gathering pipelines in the Gulf Coast region;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>The Mobile Bay and Markham processing plants in the Gulf Coast region;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>The Canyon Station and Devils Tower offshore production platforms in the Gulf of
Mexico;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>Four Gulf of Mexico deepwater crude oil pipelines;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>NGL storage facilities in the Conway, Kansas area;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>Interests in two NGL fractionation facilities: one near Conway, Kansas and the other in
Baton Rouge, Louisiana;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>An equity interest in Discovery Producer Services LLC, whose assets include a
processing plant and a fractionation plant in Louisiana, and an offshore natural gas
gathering and transportation system in the Gulf of Mexico;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>An equity interest in Aux Sable Liquid Products LP, whose assets include a processing
plant and a fractionator in Illinois;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>An equity interest in Overland Pass Pipeline Company LLC, whose assets include a
natural gas liquids pipeline stretching from Wyoming through Colorado and into Kansas.</td>
</tr>
</table>
</div>
<!-- Folio -->
<!-- /Folio -->
</div>
<!-- PAGEBREAK -->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 0pt">
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note 2 - us-gaap:PartnersCapitalNotesDisclosureTextBlock-->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b>Note 2. Allocation of Net Income and Distributions</b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The allocation of net income among our general partner, limited partners, and noncontrolling
interests for the three months ended March 31, 2011 and 2010, is as follows:
</div>
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="76%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6" style="border-bottom: 1px solid #000000"><b>Three months ended March 31,</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>2011</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>2010</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6"><b>(Millions)</b></td>
<td> </td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Allocation of net income to general partner:<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Net income<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">307</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">322</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Net income applicable to pre-partnership operations <sup style="font-size: 85%; vertical-align: text-top"> </sup> allocated to general partner
</div></td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="left"> </td>
<td align="right">(172</td>
<td nowrap="nowrap">)</td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Net income applicable to noncontrolling interests<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="left"> </td>
<td align="right">(6</td>
<td nowrap="nowrap">)</td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Net reimbursable costs charged directly to general partner<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td nowrap="nowrap" align="left"> </td>
<td align="right">(2</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td nowrap="nowrap" align="left"> </td>
<td align="right">(2</td>
<td nowrap="nowrap">)</td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Income subject to 2% allocation of general partner interest<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td> </td>
<td align="right">305</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">142</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">General partner’s share of net income<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td nowrap="nowrap" align="left"> </td>
<td align="right">2.0</td>
<td nowrap="nowrap">%</td>
<td> </td>
<td nowrap="nowrap" align="left"> </td>
<td align="right">2.0</td>
<td nowrap="nowrap">%</td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">General partner’s allocated share of net income before <sup style="font-size: 85%; vertical-align: text-top"> </sup> items directly allocable to general partner interest<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td> </td>
<td align="right">6</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">3</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Incentive distributions paid to general partner<sup style="font-size: 85%; vertical-align: text-top">*</sup>
</div></td>
<td> </td>
<td> </td>
<td align="right">59</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Net reimbursable costs charged directly to general partner<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td> </td>
<td align="right">2</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">2</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Pre-partnership net income allocated to <sup style="font-size: 85%; vertical-align: text-top"> </sup> general partner interest<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">172</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Net income allocated to general partner<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">67</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">177</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Net income<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">307</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">322</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Net income allocated to general partner<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td> </td>
<td align="right">67</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">177</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Net income allocated to Class C limited partners<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">89</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Net income allocated to noncontrolling interests<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">6</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Net income allocated to common limited partners<sup style="font-size: 85%; vertical-align: text-top"> </sup>
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">240</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">50</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
<div align="left">
<div style="font-size: 3pt; margin-top: 16pt; width: 18%; border-top: 1px solid #000000"> 
</div>
</div>
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr>
<td width="3%"></td>
<td width="1%"></td>
<td width="96%"></td>
</tr>
<tr valign="top">
<td nowrap="nowrap" align="left">*</td>
<td> </td>
<td>In the calculation of basic and diluted net income per common unit, the net income allocated to the general
partner includes IDRs pertaining to the current reporting period, but paid in the subsequent period. The net
income allocated to the general partner’s capital account reflects IDRs paid during the current reporting period.</td>
</tr>
</table>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The <i>net reimbursable costs charged directly to general partner </i>may include the net of both
income and expense items. Under the terms of omnibus agreements, we are reimbursed by our general
partner for certain expense items and are required to distribute certain income items to our
general partner.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Total comprehensive income for the three months ended March 31, 2011 and 2010 is $305 million
and $310 million, respectively. The difference between total comprehensive income and net income
for all periods is due to net unrealized changes in cash flow hedges.
</div>
<!-- Folio -->
<!-- /Folio -->
</div>
<!-- PAGEBREAK -->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 0pt">
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     We paid or have authorized payment of the following partnership cash distributions during 2010
and 2011 (in millions, except for per unit amounts):
</div>
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="28%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3"><b>Incentive</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3"><b>Per Unit</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3"><b>Common</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3"><b>Class C</b></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3"><b>Distribution</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3"><b>Total Cash</b></td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td nowrap="nowrap" align="left" style="border-bottom: 1px solid #000000"><b>Payment Date</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>Distribution</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>Units</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>Units</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>2%</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>Rights</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>Distribution</b></td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">2/12/2010
</div></td>
<td> </td>
<td align="right">$</td>
<td align="right">0.6350</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">33</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">1</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">34</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">5/14/2010
</div></td>
<td> </td>
<td align="right">$</td>
<td align="right">0.6575</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">35</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">87</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">3</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">30</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">155</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">8/13/2010
</div></td>
<td> </td>
<td align="right">$</td>
<td align="right">0.6725</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">172</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">4</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">45</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">221</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">11/12/2010
</div></td>
<td> </td>
<td align="right">$</td>
<td align="right">0.6875</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">192</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">5</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">53</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">250</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">2/11/2011
</div></td>
<td> </td>
<td align="right">$</td>
<td align="right">0.7025</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">204</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">5</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">59</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">268</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">5/13/2011(a)
</div></td>
<td> </td>
<td align="right">$</td>
<td align="right">0.7175</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">208</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">5</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">63</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">276</td>
<td> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
<div align="left">
<div style="font-size: 3pt; margin-top: 16pt; width: 18%; border-top: 1px solid #000000"> 
</div>
</div>
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr>
<td width="3%"></td>
<td width="1%"></td>
<td width="96%"></td>
</tr>
<tr valign="top">
<td nowrap="nowrap" align="left">(a)</td>
<td> </td>
<td>The Board of Directors of our general partner declared this cash distribution on April 21, 2011, to be paid on
May 13, 2011, to unitholders of record at the close of business on May 6, 2011.</td>
</tr>
</table>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note 3 - wpz:OtherAccrualsDisclosuresTextBlock-->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b>Note 3. Other Accruals</b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     <i>Other income — net </i>within <i>segment costs and expenses </i>in 2011 includes $10 million
related to the reversal of project feasibility costs from expense to
capital at Gas Pipeline, associated with an expansion project, upon
determining that the related project was probable of development.
These costs will be included in the capital costs of the project,
which we belive are probable of recovery through the project rates.
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note 4 - us-gaap:InventoryDisclosureTextBlock-->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b>Note 4. Inventories</b>
</div>
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="76%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2"><b>March 31,</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2"><b>December 31,</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>2011</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>2010</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6"><b>(Millions)</b></td>
<td> </td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Natural gas liquids
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">53</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">61</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Natural gas in underground storage
</div></td>
<td> </td>
<td> </td>
<td align="right">49</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">62</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Materials, supplies, and other
</div></td>
<td> </td>
<td> </td>
<td align="right">71</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">72</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">173</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">195</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note 5 - us-gaap:FairValueDisclosuresTextBlock-->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b>Note 5. Fair Value Measurements</b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The following table presents, by level within the fair value hierarchy, our assets and
liabilities that are measured at fair value on a recurring basis.
</div>
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="20%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="14" style="border-bottom: 1px solid #000000"><b>March 31, 2011</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="14" style="border-bottom: 1px solid #000000"><b>December 31, 2010</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Level 1</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Level 2</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Level 3</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Total</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Level 1</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Level 2</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Level 3</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Total</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="14"><b>(Millions)</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="14"><b>(Millions)</b></td>
<td> </td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Assets:
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">ARO Trust investments (see Note 6)
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">38</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">38</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">40</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">40</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Energy derivatives
</div></td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">3</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">3</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:45px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:45px; text-indent:-15px">Total assets
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">38</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">3</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">41</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">40</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">40</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:45px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Liabilities:
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Energy derivatives
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">5</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">5</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:45px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:45px; text-indent:-15px">Total liabilities
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">5</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">5</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:45px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The instruments included in our Level 1 measurements consist of a portfolio of mutual
funds. (See Note 6.)
</div>
<!-- Folio -->
<!-- /Folio -->
</div>
<!-- PAGEBREAK -->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 0pt">
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The instruments included in our Level 2 measurements consist primarily of over-the-counter
(OTC) instruments such as natural gas and natural gas liquid (NGL) swaps. Swap contracts included
in Level 2 are valued using an income approach including present value techniques. Significant
inputs into our Level 2 valuations include commodity prices and interest rates, as well as
considering executed transactions or broker quotes corroborated by other market data. These broker
quotes are based on observable market prices at which transactions could currently be executed. In
certain instances where these inputs are not observable for all periods, relationships of
observable market data and historical observations are used as a means to estimate fair value.
Where observable inputs are available for substantially the full term of the asset or liability,
the instrument is categorized in Level 2.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Certain instruments trade with lower availability of pricing information. These instruments
are valued with a present value technique using inputs that may not be readily observable or
corroborated by other market data. These instruments are classified
within Level 3 because these
inputs have a significant impact on the measurement of fair value. As of March 31, 2011 and
December 31, 2010, we do not have any instruments classified as Level 3.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The tenure of our derivatives portfolio is relatively short with all of our derivatives
expiring by December 31, 2011. Due to the nature of the products and tenure, we are consistently
able to obtain market pricing. All pricing is reviewed on a daily basis and is formally validated
with broker quotes and documented on a monthly basis.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Reclassifications of fair value between Level 1, Level 2, and Level 3 of the fair value
hierarchy, if applicable, are made at the end of each quarter. No significant transfers between
Level 1 and Level 2 occurred during the period ended March 31, 2011 or 2010. During the period
ended March 31, 2011, certain NGL swaps that originated during the first quarter of 2011 were
transferred from Level 3 to Level 2. Prior to March 31, 2011, such swaps were considered Level 3
due to a lack of observable third-party market quotes. Due to an increase in exchange-traded
transactions and greater visibility from OTC trading, we transferred these instruments to Level 2.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The following table presents a reconciliation of changes in the fair value of our net energy
derivatives classified as Level 3 in the fair value hierarchy.
</div>
<div align="center" style="font-size: 10pt; margin-top: 18pt"><b>Level 3 Fair Value Measurements Using Significant Unobservable Inputs</b>
</div>
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="76%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6" style="border-bottom: 0px solid #000000"><b>Three months ended</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6" style="border-bottom: 1px solid #000000"><b>March 31,</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>2011</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>2010</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6"><b>(Millions)</b></td>
<td> </td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Beginning balance
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Realized and unrealized gains (losses):
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Included in net income
</div></td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="left"> </td>
<td align="right">(1</td>
<td nowrap="nowrap">)</td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">Included in other comprehensive income (loss)
</div></td>
<td> </td>
<td nowrap="nowrap" align="left"> </td>
<td align="right">(5</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td> </td>
<td align="right">5</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Settlements
</div></td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Transfers into Level 3
</div></td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Transfers out of Level 3
</div></td>
<td> </td>
<td> </td>
<td align="right">5</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Ending balance
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">4</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Unrealized gains (losses) included in net income relating to instruments
still held at March 31
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Realized and unrealized gains (losses) included in <i>net income </i>for the above periods are
reported in <i>revenues </i>or <i>costs and operating expenses </i>in our Consolidated Statement of Income.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     For the three months ended March 31, 2011 and 2010, there were no assets or liabilities
measured at fair value on a nonrecurring basis.
</div>
<!-- Folio -->
<!-- /Folio -->
</div>
<!-- PAGEBREAK -->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 0pt">
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note 6 - wpz:FinancialInstrumentsDerivativesAndGuaranteesTextBlock-->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b>Note 6. Financial Instruments, Derivatives, and Guarantees</b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt"><b><i>Financial Instruments</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">   <i>Fair-value methods</i>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     We use the following methods and assumptions in estimating our fair-value disclosures for
financial instruments:
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     <u><i>Cash and cash equivalents</i></u><i>: </i>The carrying amounts reported in the Consolidated Balance
Sheet approximate fair value due to the short-term maturity of these instruments.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     <u><i>ARO Trust investments</i></u><i>: </i>Pursuant to its 2008 rate case settlement, Transco deposits a
portion of its collected rates into an external trust (ARO Trust) that is specifically designated
to fund future asset retirement obligations. The ARO Trust invests in a portfolio of mutual funds
that are reported at fair value in <i>regulatory assets, deferred charges and other </i>in the
Consolidated Balance Sheet and are classified as available-for-sale. However, both realized and
unrealized gains and losses are ultimately recorded as regulatory assets or liabilities.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     <u><i>Long-term debt</i></u><i>: </i>The fair value of our publicly traded long-term debt is determined
using indicative period-end traded bond market prices. At both March 31, 2011 and December 31,
2010, approximately 100 percent of our long-term debt was publicly traded.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     <u><i>Energy derivatives</i></u><i>: </i>Energy derivatives include forwards and swaps. These are carried
at fair value in <i>other current assets </i>and <i>other accrued liabilities </i>in the Consolidated Balance
Sheet. See Note 5 for a discussion of the valuation of our energy derivatives.
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt">   <i>Carrying amounts and fair values of our financial instruments</i>
</div>
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="52%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
<td width="5%"> </td>
<td width="3%"> </td>
<td width="1%"> </td>
<td width="3%"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="7" style="border-bottom: 1px solid #000000"><b>March 31, 2011</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="7" style="border-bottom: 1px solid #000000"><b>December 31, 2010</b></td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3"><b>Carrying</b></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3"><b>Carrying</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>Amount</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>Fair Value</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>Amount</b></td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="3" style="border-bottom: 1px solid #000000"><b>Fair Value</b></td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="15"><b>(Millions)</b></td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td align="center">
<div style="margin-left:15px; text-indent:-15px"><b>Asset (Liability)</b>
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Cash and cash equivalents
</div></td>
<td> </td>
<td align="right">$</td>
<td align="right">232</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">232</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">187</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">187</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">ARO Trust investments
</div></td>
<td> </td>
<td align="right">$</td>
<td align="right">38</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">38</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">40</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">40</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Long-term debt, including current portion
</div></td>
<td> </td>
<td nowrap="nowrap" align="right">$</td>
<td align="right">(6,824</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td nowrap="nowrap" align="right">$</td>
<td align="right">(7,272</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td nowrap="nowrap" align="right">$</td>
<td align="right">(6,823</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td nowrap="nowrap" align="right">$</td>
<td align="right">(7,283</td>
<td nowrap="nowrap">)</td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Energy commodity cash flow hedges
</div></td>
<td> </td>
<td nowrap="nowrap" align="right">$</td>
<td align="right">(2</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td nowrap="nowrap" align="right">$</td>
<td align="right">(2</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td align="right">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="right">$</td>
<td align="right">—</td>
<td> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b><i>Energy Commodity Derivatives</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">   <i>Risk management activities</i>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     We are exposed to market risk from changes in energy commodity prices within our operations.
We may utilize derivatives to manage our exposure to the variability in expected future cash flows
from forecasted purchases of natural gas and forecasted sales of NGLs attributable to commodity
price risk. Certain of these derivatives utilized for risk management purposes have been designated
as cash flow hedges, while other derivatives have not been designated as cash flow hedges or do not
qualify for hedge accounting despite hedging our future cash flows on an economic basis.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     We sell NGL volumes received as compensation for certain processing services at different
locations throughout the United States. We also buy natural gas to satisfy the required fuel and
shrink needed to generate NGLs. To reduce exposure to a decrease in revenues from fluctuations in
NGL market prices or increases in costs and operating expenses from fluctuations in natural gas
market prices, we may enter into NGL or natural gas swap agreements, financial or physical forward
contracts, and financial option contracts to mitigate the price risk on forecasted sales of NGLs
and purchases of natural gas. Those designated as cash flow hedges are expected to be highly
effective in offsetting cash flows attributable to the hedged risk during the term of the hedge.
However, ineffectiveness may be recognized primarily as a result of locational differences between
the hedging derivative and the hedged item.
</div>
<!-- Folio -->
<!-- /Folio -->
</div>
<!-- PAGEBREAK -->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 0pt">
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt">   <i>Volumes</i>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Our energy commodity derivatives are comprised of both contracts to purchase commodities (long
positions) and contracts to sell commodities (short positions). Derivative transactions are
categorized into two types:
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>Central hub risk<i>: </i>Financial derivative exposures to Henry Hub for natural gas and Mont
Belvieu for NGLs;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>Basis risk<i>: </i>Financial derivative exposures to the difference in value between the
central hub and another specific delivery point.</td>
</tr>
</table>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The following table depicts the notional quantities of the net long (short) positions in our
commodity derivatives portfolio as of March 31, 2011. Natural gas is presented in millions of
British Thermal Units (MMBtu) and NGLs are presented in gallons.
</div>
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="18%"> </td>
<td width="5%"> </td>
<td width="23%"> </td>
<td width="5%"> </td>
<td width="9%"> </td>
<td width="5%"> </td>
<td width="17%"> </td>
<td width="5%"> </td>
<td width="13%"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center"><b>Unit of</b></td>
<td> </td>
<td nowrap="nowrap" align="center"><b>Central Hub</b></td>
<td> </td>
<td nowrap="nowrap" align="center"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td nowrap="nowrap" align="left" colspan="3" style="border-bottom: 1px solid #000000"><b>Derivative Notional Volumes</b></td>
<td> </td>
<td nowrap="nowrap" align="center" style="border-bottom: 1px solid #000000"><b>Measurement</b></td>
<td> </td>
<td nowrap="nowrap" align="center" style="border-bottom: 1px solid #000000"><b>Risk</b></td>
<td> </td>
<td nowrap="nowrap" align="center" style="border-bottom: 1px solid #000000"><b>Basis Risk</b></td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td colspan="3" align="left"><b>Designated as Hedging Instruments</b></td>
<td> </td>
<td align="center" valign="top"> </td>
<td> </td>
<td align="center" valign="top"> </td>
<td> </td>
<td align="center" valign="top"> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Midstream
</div></td>
<td> </td>
<td align="left" valign="top">Risk Management</td>
<td> </td>
<td align="center" valign="top">MMBtu</td>
<td> </td>
<td align="center" valign="top">8,250,000</td>
<td> </td>
<td align="center" valign="top">7,562,500</td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Midstream
</div></td>
<td> </td>
<td align="left" valign="top">Risk Management</td>
<td> </td>
<td align="center" valign="top">Gallons</td>
<td> </td>
<td align="center" valign="top">(2,280,000)</td>
<td> </td>
<td align="center" valign="top"> </td>
</tr>
<tr valign="bottom">
<td colspan="3" align="left"><b>Not Designated as Hedging Instruments</b></td>
<td> </td>
<td align="center" valign="top"> </td>
<td> </td>
<td align="center" valign="top"> </td>
<td> </td>
<td align="center" valign="top"> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Midstream
</div></td>
<td> </td>
<td align="left" valign="top">Risk Management</td>
<td> </td>
<td align="center" valign="top">Gallons</td>
<td> </td>
<td align="center" valign="top">(50,000)</td>
<td> </td>
<td align="center" valign="top"> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="1%" nowrap="nowrap" align="left"> </td>
<td width="1%"> </td>
<td>   <i>Fair values and gains (losses)</i></td>
</tr>
</table>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The following table presents the fair value of energy commodity derivatives. Our derivatives
are included in <i>other current assets </i>and <i>other accrued liabilities </i>in our Consolidated Balance
Sheet. Derivatives are classified as current or noncurrent based on the contractual timing of
expected future net cash flows of individual contracts. The expected future net cash flows for
derivatives classified as current are expected to occur by December
2011.
</div>
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="52%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6" style="border-bottom: 1px solid #000000"><b>March 31,</b> <b>2011</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6" style="border-bottom: 1px solid #000000"><b>December 31, 2010</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Assets</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Liabilities</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Assets</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Liabilities</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6"><b>(Millions)</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6"><b>(Millions)</b></td>
<td> </td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Designated as hedging instruments
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">3</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">5</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Not designated as hedging instruments
</div></td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">—</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">Total derivatives
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">3</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">5</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The following table presents gains and losses for our energy commodity derivatives designated
as cash flow hedges, as recognized in AOCI, <i>revenues, or costs and operating expenses.</i>
</div>
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="64%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6" style="border-bottom: 1px solid #000000"><b>Three months ended March 31,</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2"> </td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>2011</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>2010</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Classification</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="6"><b>(Millions)</b></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Net gain (loss) recognized in other comprehensive
income (loss) (effective portion)
</div></td>
<td> </td>
<td nowrap="nowrap" align="left">$</td>
<td align="right">(2</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td nowrap="nowrap" align="left">$</td>
<td align="right">(6</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td colspan="3" nowrap="nowrap" align="center">AOCI</td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Net gain (loss) reclassified from accumulated other
comprehensive income (loss) into income
(effective portion)
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="left">$</td>
<td align="right">(2</td>
<td nowrap="nowrap">)</td>
<td> </td>
<td colspan="3" nowrap="nowrap" align="center">Revenues or Costs and Operating Expenses</td>
</tr>
<tr valign="bottom"><!-- Blank Space -->
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Gain (loss) recognized in income (ineffective portion)
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">—</td>
<td> </td>
<td> </td>
<td colspan="3" align="center">Revenues or Costs and Operating Expenses</td>
</tr>
<!-- End Table Body -->
</table>
</div>
<!-- Folio -->
<!-- /Folio -->
</div>
<!-- PAGEBREAK -->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 0pt">
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     There were no gains or losses recognized in income as a result of excluding amounts from the
assessment of hedge effectiveness or as a result of reclassifications to earnings following the
discontinuance of any cash flow hedges. As of March 31, 2011, we have hedged portions of future
cash flows associated with anticipated NGL sales and natural gas purchases through 2011. Based on
recorded values at March 31, 2011, net losses to be reclassified into earnings by December 31,
2011, are $2 million. These recorded values are based on market prices of the commodities as of
March 31, 2011. Due to the volatile nature of commodity prices and changes in the creditworthiness
of counterparties, actual gains or losses realized by December 31, 2011, will likely differ from
these values. These gains or losses will offset net losses or gains that will be realized in
earnings from previous unfavorable or favorable market movements associated with underlying hedged
transactions.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     We recognized losses of less than $1 million in <i>revenues </i>for both the three months ended March
31, 2011 and 2010 on our energy commodity derivatives not designated as hedging instruments.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The cash flow impact of our derivative activities is presented in the Consolidated Statement
of Cash Flows as <i>changes in other assets and deferred charges </i>and <i>changes in accrued liabilities</i>.
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt">   <i>Credit-risk-related features</i>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The majority of our financial swap contracts are with our affiliate, Williams Gas Marketing,
Inc., and the derivative contracts not designated as cash flow hedging instruments are primarily
NGL swaps. These agreements do not contain any provisions that require us to post collateral
related to net liability positions.
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b><i>Guarantees</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     We are required by our revolving credit agreement to indemnify lenders for any taxes required
to be withheld from payments due to the lenders and for any tax payments made by the lenders. The
maximum potential amount of future payments under these indemnifications is based on the related
borrowings and such future payments cannot currently be determined. These indemnifications
generally continue indefinitely unless limited by the underlying tax regulations and have no
carrying value. We have never been called upon to perform under these indemnifications and have no
current expectation of a future claim.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     At March 31, 2011, we do not expect these guarantees to have a material impact on our future
liquidity or financial position. However, if we are required to perform on these guarantees in the
future, it may have a material adverse effect on our results of operations.
</div>
<!-- Folio -->
<!-- /Folio -->
</div>
<!-- PAGEBREAK -->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 0pt">
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note 7 - us-gaap:CommitmentsAndContingenciesDisclosureTextBlock-->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b>Note 7. Contingent Liabilities</b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt"><b><i>Environmental Matters</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Our interstate gas pipelines are involved in remediation activities related to certain
facilities and locations for polychlorinated biphenyl, mercury contamination, and other hazardous
substances. These activities have involved the U.S. Environmental Protection Agency
(EPA), various state environmental authorities and identification as a potentially responsible
party at various Superfund waste sites. At March 31, 2011, we have accrued liabilities of $12
million for these costs. We expect that these costs will be recoverable through rates.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     In September 2007, the EPA requested, and Transco later provided, information regarding
natural gas compressor stations in the states of Mississippi and Alabama as part of the EPA’s
investigation of our compliance with the Clean Air Act. On March 28, 2008, the EPA issued notices
of violation alleging violations of Clean Air Act requirements at these compressor stations.
Transco met with the EPA in May 2008 and submitted its response denying the allegations in June
2008. The EPA has requested additional information pertaining to these compressor stations, most
recently in February 2011. In August 2010, the EPA requested, and Transco later provided, similar
information for a compressor station in Maryland.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     In March 2008, the EPA proposed a penalty of $370,000 for alleged violations relating to leak
detection and repair program delays at our Ignacio gas plant in Colorado and for alleged permit
violations at a compressor station. Tentative settlement has been reached in first-quarter 2011.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     We also accrue environmental remediation costs for natural gas underground storage facilities,
primarily related to soil and groundwater contamination. At March 31, 2011, we have accrued
liabilities totaling $7 million for these costs.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The EPA and various state regulatory agencies routinely promulgate and propose new rules, and
issue updated guidance to existing rules. These new rules and rulemakings include, but are not
limited to, rules for reciprocating internal combustion engine maximum achievable control
technology, new air quality standards for ground level ozone, and one hour nitrogen dioxide
emission limits. We are unable to estimate the costs of asset additions or modifications necessary
to comply with these new regulations due to uncertainty created by the various legal challenges to
these regulations and the need for further specific regulatory guidance.
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b><i>Rate Matters</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     On
August 31, 2006, Transco submitted to the Federal Energy
Regulatory Commission (FERC) a general rate filing (Docket No. RP06-569)
principally designed to recover increased costs. The rates became effective March 1, 2007, subject
to refund and the outcome of a hearing. All issues in this proceeding except one have been resolved
by settlement.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The one issue reserved for litigation or further settlement relates to Transco’s proposal to
change the design of the rates for service under one of its storage rate schedules, which was
implemented subject to refund on March 1, 2007. A hearing on that issue was held before a FERC
Administrative Law Judge (ALJ) in July 2008. In November 2008, the ALJ issued an initial decision
in which he determined that Transco’s proposed incremental rate design is unjust and unreasonable.
On January 21, 2010, the FERC reversed the ALJ’s initial decision, and approved our proposed
incremental rate design. Certain parties have sought rehearing of the FERC’s order. If the FERC
were to reverse their opinion on rehearing, we believe any refunds would not be material to our
results of operations.
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b><i>Safety Matters</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Transco and Northwest Pipeline have developed an Integrity Management Plan that we believe
meets the United States Department of Transportation Pipeline and Hazardous Materials Safety
Administration final rule that was issued pursuant to the requirements of the Pipeline Safety
Improvement Act of 2002. The rule requires gas pipeline operators to develop an integrity
management program for transmission pipelines that could affect high consequence areas in the event
of pipeline failure. The Integrity Management Program includes a baseline assessment plan along
with periodic reassessments to be completed within required timeframes. In meeting the integrity
regulations, they have identified high consequence areas and developed baseline assessment plans.
They are on schedule to complete
the required assessments within required timeframes. Currently, we estimate the cost to
complete the required initial assessments over the period of 2011 through 2012 and associated
remediation will be primarily capital in nature and range between $80 million and $110 million for
Transco and between $50 million and $60 million for Northwest Pipeline. Ongoing periodic
reassessments and initial assessments of any new high consequence areas will be completed within
the timeframes required by the rule. Management considers the costs associated with compliance
with the rule to be prudent costs incurred in the ordinary course of business, and, therefore,
recoverable through our rates.
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b><i>Other</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     In addition to the foregoing, various other proceedings are pending against us which are
incidental to our operations.
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b><i>Summary</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Litigation, arbitration, regulatory matters and environmental matters are subject to inherent
uncertainties. Were an unfavorable ruling to occur, there exists the possibility of a material
adverse impact on the results of operations in the period in which the ruling occurs. Management,
including internal counsel, currently believes that the ultimate resolution of the foregoing
matters, taken as a whole and after consideration of amounts accrued, insurance coverage, recovery
from customers or other indemnification arrangements, will not have a material adverse effect upon
our future liquidity or financial position.
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note 8 - us-gaap:SegmentReportingDisclosureTextBlock-->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b>Note 8. Segment Disclosures</b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     Our reportable segments are strategic business units that offer different products and
services. The segments are managed separately because each segment requires different technology,
marketing strategies and industry knowledge.
</div>
<div align="left" style="font-size: 10pt; margin-top: 12pt">   <b><i>Performance Measurement</i></b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     We currently evaluate segment operating performance based on <i>segment profit </i>from operations,
which includes <i>segment revenues </i>from external and internal customers, <i>segment costs and expenses,</i>
and <i>equity earnings</i>.
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The primary types of costs and operating expenses by segment can be generally summarized as
follows:
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>Gas Pipeline — depreciation and operation and maintenance expenses;</td>
</tr>
</table>
</div>
<div style="margin-top: 6pt">
<table width="100%" border="0" cellpadding="0" cellspacing="0" style="font-size: 10pt; text-align: left">
<tr valign="top" style="font-size: 10pt; color: #000000; background: transparent">
<td width="2%" style="background: transparent"> </td>
<td width="3%" nowrap="nowrap" align="left"><b>•</b></td>
<td width="1%"> </td>
<td>Midstream — commodity purchases (primarily for NGL and crude marketing, shrink and
fuel), depreciation, and operation and maintenance expenses.</td>
</tr>
</table>
</div>
<!-- Folio -->
<!-- /Folio -->
</div>
<!-- PAGEBREAK -->
<div style="font-family: 'Times New Roman',Times,serif">
<div style="margin-top: 0pt">
</div>
<div align="left" style="font-size: 10pt; margin-top: 0pt">
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     The following table reflects the reconciliation of <i>segment revenues </i>to <i>revenues </i>and <i>segment
profit </i>to <i>operating income </i>as reported in the Consolidated
Statement of Income.
</div>
<div align="center">
<table style="font-size: 10pt; text-align: left" cellspacing="0" border="0" cellpadding="0" width="100%">
<!-- Begin Table Head -->
<tr valign="bottom">
<td width="64%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
<td width="5%"> </td>
<td width="1%"> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Gas Pipeline</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Midstream</b></td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="2" style="border-bottom: 1px solid #000000"><b>Total</b></td>
<td> </td>
</tr>
<tr style="font-size: 8pt" valign="bottom">
<td> </td>
<td> </td>
<td nowrap="nowrap" align="center" colspan="10"><b>(Millions)</b></td>
<td> </td>
</tr>
<!-- End Table Head -->
<!-- Begin Table Body -->
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px"><b><i>Three months ended March 31, 2011</i></b>
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Segment revenues:
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:30px; text-indent:-15px">External
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">416</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">1,163</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">1,579</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Total revenues
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">416</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">1,163</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">1,579</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Segment profit
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">175</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">262</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">437</td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Less equity earnings
</div></td>
<td> </td>
<td> </td>
<td align="right">9</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">16</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">25</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Segment operating income
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">166</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">246</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">412</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 0px double #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">General corporate expenses
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="left"> </td>
<td align="right">(30</td>
<td nowrap="nowrap">)</td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Total operating income
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">382</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom"><!-- Blank Space -->
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px"><b><i>Three months ended March 31, 2010</i></b>
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Segment revenues:
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:30px; text-indent:-15px">External
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">407</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">1,083</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">1,490</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Total revenues
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">407</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">1,083</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">1,490</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Segment profit
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">169</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">255</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">424</td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">Less equity earnings
</div></td>
<td> </td>
<td> </td>
<td align="right">9</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">17</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">26</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Segment operating income
</div></td>
<td> </td>
<td align="left">$</td>
<td align="right">160</td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">238</td>
<td> </td>
<td> </td>
<td> </td>
<td align="right">398</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:30px; text-indent:-15px"> 
</div></td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 0px double #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom" style="background: #cceeff">
<td>
<div style="margin-left:15px; text-indent:-15px">General corporate expenses
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" align="left"> </td>
<td align="right">(35</td>
<td nowrap="nowrap">)</td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 1px solid #000000"> </td>
<td> </td>
</tr>
<tr valign="bottom">
<td>
<div style="margin-left:15px; text-indent:-15px">Total operating income
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td align="left">$</td>
<td align="right">363</td>
<td> </td>
</tr>
<tr style="font-size: 1px">
<td>
<div style="margin-left:15px; text-indent:-15px"> 
</div></td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td> </td>
<td nowrap="nowrap" colspan="2" align="right" style="border-top: 3px double #000000"> </td>
<td> </td>
</tr>
<!-- End Table Body -->
</table>
</div>
</div>
<!--DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" -->
<!-- Begin Block Tagged Note 9 - us-gaap:ScheduleOfSubsequentEventsTextBlock-->
<div style="font-family: 'Times New Roman',Times,serif">
<div align="left" style="font-size: 10pt; margin-top: 12pt"><b>Note 9. Subsequent Event</b>
</div>
<div align="left" style="font-size: 10pt; margin-top: 6pt">     During April 2011, we agreed to acquire from Williams an additional 24.5 percent interest in
Gulfstream in exchange for aggregate consideration of $297 million of cash, 632,584 of our limited
partner units, and an increase in the capital account of our general partner to allow it to
maintain its 2 percent general partner interest. We expect to fund the cash consideration for this
transaction through our credit facility.
Since the additional 24.5 percent interest was acquired from an entity under the common control of Williams,
it will be recorded at Williams’ historical book value which was approximately $185 million at March 31, 2011.
The transaction is expected to close during the second
quarter 2011.
</div>
</div>
false
--12-31
Q1
2011
2011-03-31
10-Q
0001324518
289844575
Yes
Large Accelerated Filer
1789200841
Williams Partners L.P.
No
Yes
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