The Williams Companies, Inc. (WMB) 10-K 26 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 22, 2016	Jun. 30, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	Williams Companies Inc
Entity Central Index Key	107,263
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Amendment Flag	false
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 39,345,468,396
Entity Common Stock, Shares Outstanding		750,065,665

Consolidated Statement of Opera

Consolidated Statement of Operations - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Revenues:
Service revenues	$ 5,164		$ 4,116	$ 2,939
Product sales	2,196		3,521	3,921
Total revenues	7,360		7,637	6,860
Costs and expenses:
Product costs	1,779		3,016	3,027
Operating and maintenance expenses	1,655		1,492	1,097
Depreciation and amortization expenses	1,738		1,176	815
Selling, general, and administrative expenses	741		661	512
Impairment of goodwill	1,098		0	0
Net insurance recoveries – Geismar Incident	(126)		(232)	(40)
Other (income) expense – net	249		(45)	74
Total costs and expenses	7,134		6,068	5,485
Operating income (loss)	226		1,569	1,375
Equity earnings (losses)	335		144	134
Gain on remeasurement of equity-method investment	0		2,544	0
Impairment of equity-method investments	(1,359)		0	0
Other investing income (loss) – net	27		43	81
Interest incurred	(1,118)		(888)	(611)
Interest capitalized	74		141	101
Other income (expense) – net	102		31	0
Income (loss) from continuing operations before income taxes	(1,713)		3,584	1,080
Provision (benefit) for income taxes	(399)		1,249	401
Income (loss) from continuing operations	(1,314)		2,335	679
Income (loss) from discontinued operations	0		4	(11)
Net income (loss)	(1,314)		2,339	668
Less: Net income (loss) attributable to noncontrolling interests	(743)		225	238
Net income (loss) attributable to The Williams Companies, Inc.	(571)		2,114	430
Amounts attributable to The Williams Companies, Inc.:
Income (loss) from continuing operations	(571)		2,110	441
Income (loss) from discontinued operations	0		4	(11)
Net income (loss) attributable to The Williams Companies, Inc.	$ (571)		$ 2,114	$ 430
Basic earnings (loss) per common share:
Income (loss) from continuing operations	$ (0.76)		$ 2.93	$ 0.65
Income (loss) from discontinued operations	0		0.01	(0.02)
Net income (loss)	$ (0.76)		$ 2.94	$ 0.63
Weighted-average shares (thousands)	749,271		719,325	682,948
Diluted earnings (loss) per common share:
Income (loss) from continuing operations	$ (0.76)		$ 2.91	$ 0.64
Income (loss) from discontinued operations	0		0.01	(0.02)
Net income (loss)	$ (0.76)		$ 2.92	$ 0.62
Weighted-average shares (thousands)	749,271	[1]	723,641	687,185
[1]	For the year ended December 31, 2015, 1.7 million weighted-average nonvested restricted stock units and 1.5 million weighted-average stock options have been excluded from the computation of diluted earnings (loss) per common share as their inclusion would be antidilutive due to our loss from continuing operations attributable to The Williams Companies, Inc.

Consolidated Statement of Compr

Consolidated Statement of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Comprehensive income (loss):
Net income (loss)	$ (1,314)	$ 2,339	$ 668
Cash flow hedging activities:
Net unrealized gain (loss) from derivative instruments, net of taxes	6	0	1
Reclassifications into earnings of net derivative instruments (gain) loss, net of taxes	(6)	0	(1)
Foreign currency translation adjustments, net of taxes	(204)	(96)	(41)
Pension and other postretirement benefits:
Prior service credit (cost) arising during the year, net of taxes	0	(1)	14
Amortization of prior service cost (credit) included in net periodic benefit cost, net of taxes	(3)	(5)	(2)
Net actuarial gain (loss) arising during the year, net of taxes	8	(100)	189
Amortization of actuarial (gain) loss included in net periodic benefit cost, net of taxes	28	26	38
Other comprehensive income (loss)	(171)	(176)	198
Comprehensive income (loss)	(1,485)	2,163	866
Less: Comprehensive income (loss) attributable to noncontrolling interests	(813)	206	238
Comprehensive Income (loss) attributable to The Williams Companies, Inc.	$ (672)	$ 1,957	$ 628

Consolidated Statement of Comp4

Consolidated Statement of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Comprehensive Income Derivatives Qualifying As Hedges Tax Effect Period Increase Decrease [Abstract]
Other Comprehensive Income, Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	$ 0	$ 0	$ 0
Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Tax	1	0	0
Other Comprehensive Income (Loss), Tax [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	31	18	24
Other Comprehensive Income Defined Benefit Plans Tax [Abstract]
Other Comprehensive Income Loss Pension And Other Postretirement Benefit Plans, Benefit Plan Improvement, Tax Effect	0	0	(9)
Other Comprehensive Income Amortization Of Defined Benefit Plan Net Prior Service Cost Recognized In Net Periodic Pension Cost Tax	3	3	1
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax	(5)	60	(111)
Other Comprehensive Income Loss Reclassification Pension And Other Postretirement Benefit Plans Net Gain Loss Recognized In Net Periodic Benefit Cost Tax	$ (18)	$ (15)	$ (23)

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 100	$ 240
Accounts and notes receivable (net of allowance of $3 at December 31, 2015 and $0 at December 31, 2014):
Trade and other	1,034	972
Income tax receivable	7	167
Deferred income tax assets	42	67
Inventories	127	231
Other current assets and deferred charges	217	213
Total current assets	1,527	1,890
Investments	7,336	8,400
Property, plant, and equipment – net	29,579	28,081
Goodwill	47	1,120
Other intangible assets – net of accumulated amortization	9,970	10,453
Regulatory assets, deferred charges, and other	561	511
Total assets	49,020	50,455
Current liabilities:
Accounts payable	744	865
Accrued liabilities	1,078	900
Commercial paper	499	798
Long-term debt due within one year	176	4
Total current liabilities	2,497	2,567
Long-term debt	23,812	20,780
Deferred income tax liabilities	4,218	4,712
Other noncurrent liabilities	$ 2,268	$ 2,224
Contingent liabilities and commitments (Note 18)
Stockholders’ equity:
Common stock (960 million shares authorized at $1 par value; 784 million shares issued at December 31, 2015 and 782 million shares issued at December 31, 2014)	$ 784	$ 782
Capital in excess of par value	14,807	14,925
Retained deficit	(7,960)	(5,548)
Accumulated other comprehensive income (loss)	(442)	(341)
Treasury stock, at cost (35 million shares of common stock)	(1,041)	(1,041)
Total stockholders’ equity	6,148	8,777
Noncontrolling interests in consolidated subsidiaries	10,077	11,395
Total equity	16,225	20,172
Total liabilities and equity	$ 49,020	$ 50,455

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Stockholders’ equity:
Common Stock, Shares Authorized	960	960
Common Stock, Par or Stated Value Per Share	$ 1	$ 1
Common Stock, Shares Issued	784	782
Treasury Stock, Shares	35	35
Allowance for Doubtful Accounts Receivable, Current	$ 3	$ 0

Consolidated Statement of Chang

Consolidated Statement of Changes in Equity - USD ($) $ in Millions	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings (Deficit)	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Total Stockholders' Equity	Noncontrolling Interests
Beginning balance at Dec. 31, 2012	$ 7,427	$ 716	$ 11,134	$ (5,695)	$ (362)	$ (1,041)	$ 4,752	$ 2,675
Net income (loss)	668	0	0	430	0	0	430	238
Other comprehensive income (loss)	198	0	0	0	198	0	198	0
Cash dividends - common stock (Note 15)	(982)	0	0	(982)	0	0	(982)	0
Dividends and distributions to noncontrolling interests	(489)	0	0	0	0	0	0	(489)
Issuance of common stock from debentures conversion	1	0	1	0	0	0	1	0
Stock-based compensation and related common stock issuances, net of tax	56	2	54	0	0	0	56	0
Sales of limited partner units of Williams Partners L.P.	1,819	0	0	0	0	0	0	1,819
Changes in ownership of consolidated subsidiaries, net	(243)	0	409	0	0	0	409	(652)
Contributions from noncontrolling interests	467	0	0	0	0	0	0	467
Other	(1)	0	1	(1)	0	0	0	(1)
Net increase (decrease) in equity	1,494	2	465	(553)	198	0	112	1,382
Ending balance at Dec. 31, 2013	8,921	718	11,599	(6,248)	(164)	(1,041)	4,864	4,057
Net income (loss)	2,339	0	0	2,114	0	0	2,114	225
Other comprehensive income (loss)	(176)	0	0	0	(157)	0	(157)	(19)
Noncontrolling interest resulting from acquisition of business (Note 2)	7,502	0	0	0	0	0	0	7,502
Cash dividends - common stock (Note 15)	(1,412)	0	0	(1,412)	0	0	(1,412)	0
Dividends and distributions to noncontrolling interests	(840)	0	0	0	0	0	0	(840)
Stock-based compensation and related common stock issuances, net of tax	88	3	85	0	0	0	88	0
Sales of limited partner units of Williams Partners L.P.	55	0	0	0	0	0	0	55
Changes in ownership of consolidated subsidiaries, net	44	0	(73)	0	(20)	0	(93)	137
Issuance of common stock for acquisition of business (Note 15)	3,378	61	3,317	0	0	0	3,378	0
Contributions from noncontrolling interests	340	0	0	0	0	0	0	340
Deconsolidation of Bluegrass Pipeline (Note 5)	(63)	0	0	0	0	0	0	(63)
Other	(4)	0	(3)	(2)	0	0	(5)	1
Net increase (decrease) in equity	11,251	64	3,326	700	(177)	0	3,913	7,338
Ending balance at Dec. 31, 2014	20,172	782	14,925	(5,548)	(341)	(1,041)	8,777	11,395
Net income (loss)	(1,314)	0	0	(571)	0	0	(571)	(743)
Other comprehensive income (loss)	(171)	0	0	0	(101)	0	(101)	(70)
Cash dividends - common stock (Note 15)	(1,836)	0	0	(1,836)	0	0	(1,836)	0
Dividends and distributions to noncontrolling interests	(942)	0	0	0	0	0	0	(942)
Stock-based compensation and related common stock issuances, net of tax	30	2	28	0	0	0	30	0
Sales of limited partner units of Williams Partners L.P.	59	0	0	0	0	0	0	59
Changes in ownership of consolidated subsidiaries, net	94	0	(160)	0	0	0	(160)	254
Contributions from noncontrolling interests	111	0	0	0	0	0	0	111
Other	22	0	14	(5)	0	0	9	13
Net increase (decrease) in equity	(3,947)	2	(118)	(2,412)	(101)	0	(2,629)	(1,318)
Ending balance at Dec. 31, 2015	$ 16,225	$ 784	$ 14,807	$ (7,960)	$ (442)	$ (1,041)	$ 6,148	$ 10,077

Consolidated Statement of Cash

Consolidated Statement of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
OPERATING ACTIVITIES:
Net income (loss)	$ (1,314)	$ 2,339	$ 668
Adjustments to reconcile to net cash provided (used) by operating activities:
Depreciation and amortization	1,738	1,176	815
Provision (benefit) for deferred income taxes	(337)	1,264	424
Impairment of goodwill	1,098	0	0
Impairment of equity-method investments	1,359	0	0
Impairment of and net (gain) loss on sale of Property, plant, and equipment	215	67	29
Amortization of stock-based awards	82	53	37
Gain on remeasurement of equity-method investment	0	(2,544)	0
Cash provided (used) by changes in current assets and liabilities:
Accounts and notes receivable	39	(276)	35
Inventories	105	(36)	(17)
Other current assets and deferred charges	4	(44)	25
Accounts payable	(90)	(8)	(35)
Accrued liabilities	26	(203)	175
Other, including changes in noncurrent assets and liabilities	(247)	327	61
Net cash provided (used) by operating activities	2,678	2,115	2,217
FINANCING ACTIVITIES:
Proceeds from (payments of) commercial paper – net	(306)	572	224
Proceeds from long-term debt	9,772	7,321	2,699
Payments of long-term debt	(6,516)	(1,828)	(2,081)
Proceeds from issuance of common stock	27	3,416	18
Proceeds from sale of limited partner units of consolidated partnership	59	55	1,819
Dividends paid	(1,836)	(1,412)	(982)
Dividends and distributions paid to noncontrolling interests	(942)	(840)	(489)
Contributions from noncontrolling interests	111	340	467
Payments for debt issuance costs	(35)	(40)	(15)
Special distribution from Gulfstream	396	0	0
Contribution to Gulfstream for repayment of debt	(248)	0	0
Other – net	(1)	17	17
Net cash provided (used) by financing activities	481	7,601	1,677
INVESTING ACTIVITIES:
Capital expenditures (1)	(3,167)	(4,031)	(3,572)
Net proceeds from dispositions	3	34	3
Purchases of businesses, net of cash acquired	(112)	(5,958)	(6)
Purchases of and contributions to equity-method investments	(595)	(482)	(455)
Other – net	572	280	(22)
Net cash provided (used) by investing activities	(3,299)	(10,157)	(4,052)
Increase (decrease) in cash and cash equivalents	(140)	(441)	(158)
Cash and cash equivalents at beginning of year	240	681	839
Cash and cash equivalents at end of year	100	240	681
(1) Increases to property, plant, and equipment	(3,024)	(3,916)	(3,653)
Changes in related accounts payable and accrued liabilities	(143)	(115)	81
Capital expenditures (1)	$ (3,167)	$ (4,031)	$ (3,572)

General, Description of Busines

General, Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
General, Description of Business, Basis of Presentation and Summary Of Significant Accounting Policies [Text Block]	Note 1 – General, Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies General Unless the context clearly indicates otherwise, references in this report to “Williams,” “we,” “our,” “us,” or like terms refer to The Williams Companies, Inc. and its subsidiaries. Unless the context clearly indicates otherwise, references to “Williams,” “we,” “our,” and “us” include the operations in which we own interests accounted for as equity-method investments that are not consolidated in our financial statements. When we refer to our equity investees by name, we are referring exclusively to their businesses and operations. Energy Transfer Merger Agreement On September 28, 2015, we entered into an Agreement and Plan of Merger (Merger Agreement) with Energy Transfer Equity, L.P. (Energy Transfer) and certain of its affiliates. The Merger Agreement provides that, subject to the satisfaction of customary closing conditions, we will be merged with and into the newly formed Energy Transfer Corp LP (ETC) (ETC Merger), with ETC surviving the ETC Merger. Energy Transfer formed ETC as a limited partnership that will be treated as a corporation for U.S. federal income tax purposes. Upon completion of the ETC Merger, ETC will be publicly traded on the New York Stock Exchange under the symbol “ETC.” At the effective time of the ETC Merger, each issued and outstanding share of our common stock (except for certain shares such as those held by us or our subsidiaries and any held by ETC and its affiliates) will be canceled and automatically converted into the right to receive, at the election of each holder and subject to proration as set forth in the Merger Agreement (collectively Merger Consideration): • 1.8716 common shares representing limited partnership interests in ETC (ETC common shares) (Stock Consideration); or • $43.50 in cash (Cash Consideration); or • $8.00 in cash and 1.5274 ETC common shares (Mixed Consideration). Elections to receive the Stock Consideration or the Cash Consideration will be subject to proration to ensure that the aggregate number of ETC common shares and the aggregate amount of cash paid in the ETC Merger will be the same as if all electing shares of our common stock received the Mixed Consideration. In addition, our stockholders will receive a special one-time dividend of $0.10 per share of Williams common stock, to be paid to holder of record immediately prior to the closing of the ETC Merger and contingent upon consummation of the ETC Merger. In connection with the ETC Merger, Energy Transfer will subscribe for a number of ETC common shares at the transaction price, in exchange for the amount of cash needed by ETC to fund the cash portion of the Merger Consideration (the Parent Cash Deposit), and, as a result, based on the number of shares of Williams common stock outstanding as of the date thereof, will own approximately 19 percent of the outstanding ETC common shares immediately after the effective time of the ETC Merger. Immediately following the completion of the ETC Merger and of the LE GP, LLC (the general partner for Energy Transfer) merger with and into Energy Transfer Equity GP, LLC, ETC will contribute to Energy Transfer all of the assets and liabilities of Williams in exchange for the issuance by Energy Transfer to ETC of a number of Energy Transfer Class E common units equal to the number of ETC common shares issued to our stockholders in the ETC Merger plus the number of ETC common shares issued to Energy Transfer in consideration for the Parent Cash Deposit (such contribution, together with the ETC Merger and the other transactions contemplated by the Merger Agreement, the Merger Transactions). To address potential uncertainty as to how the newly listed ETC common shares, as a new security, will trade relative to Energy Transfer common units, each ETC common share issued in the ETC Merger, as well as the ETC common shares issued to Energy Transfer in connection with the Parent Cash Deposit, will have attached to it one contingent consideration right (CCR). The terms of the CCRs are fully described in the form of CCR Agreement attached to the Merger Agreement as Exhibit H to Exhibit 2.1 of our Form 8-K dated September 29, 2015. The receipt of the Merger Consideration is expected to be tax-free to our stockholders, except with respect to any cash consideration received. Completion of the Merger Transactions is subject to the satisfaction or waiver of a number of customary closing conditions as set forth in the Merger Agreement, including approval of the ETC Merger by our stockholders, receipt of required regulatory approvals in connection with the Merger Transactions, including the expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and effectiveness of a registration statement on Form S-4 registering the ETC common shares (and attached CCRs) to be issued in connection with the Merger Transactions. ETC filed its initial Form S-4 registration statement on November 24, 2015, and Amendment No. 1 to Form S-4 on January 12, 2016. On December 14, 2015, we and Energy Transfer issued a joint press release announcing the entry into a timing agreement with the United States Federal Trade Commission (FTC) pursuant to which both parties have agreed not to consummate ETC’s proposed acquisition of us until after the later of (i) 60 days after substantial compliance with the FTC’s request for additional information and documentary material and (ii) March 18, 2016. Termination of WPZ Merger Agreement On May 12, 2015, we entered into an agreement for a unit-for-stock transaction whereby we would have acquired all of the publicly held outstanding common units of WPZ in exchange for shares of our common stock (WPZ Merger Agreement). On September 28, 2015, prior to our entry into the Merger Agreement, we entered into a Termination Agreement and Release (Termination Agreement), terminating the WPZ Merger Agreement. Under the terms of the Termination Agreement, we are required to pay a $428 million termination fee to WPZ, of which we currently own approximately 60 percent , including the interests of the general partner and incentive distribution rights (IDRs). Such termination fee will settle through a reduction of quarterly incentive distributions we are entitled to receive from WPZ (such reduction not to exceed $209 million per quarter). The distributions from WPZ in November 2015 and February 2016 were each reduced by $209 million related to this termination fee. ACMP Merger On February 2, 2015, we completed the merger of our consolidated master limited partnerships, Williams Partners L.P. (Pre-merger WPZ ) and Access Midstream Partners, L.P. ( ACMP ) (ACMP Merger). The merged partnership is named Williams Partners L.P. Under the terms of the merger agreement, each ACMP unitholder received 1.06152 ACMP units for each ACMP unit owned immediately prior to the ACMP Merger. In conjunction with the ACMP Merger, each Pre-merger WPZ common unit held by the public was exchanged for 0.86672 ACMP common units. Each Pre-merger WPZ common unit held by us was exchanged for 0.80036 ACMP common units. Prior to the closing of the ACMP Merger, the Class D limited partner units of Pre-merger WPZ, all of which were held by us, were converted into common units on a one -for-one basis pursuant to the terms of the Pre-merger WPZ partnership agreement. Following the ACMP Merger, we own approximately 60 percent of the merged partnership, including the general partner interest and IDRs. In this report, we refer to the post-merger partnership as “WPZ” and the pre-merger entities as “Pre-merger WPZ” and “ACMP.” Description of Business We are a Delaware corporation whose common stock is listed and traded on the New York Stock Exchange. Our operations are located principally in the United States and are organized into the Williams Partners and Williams NGL & Petchem Services reportable segments. All remaining business activities are included in Other. For periods after the ACMP Acquisition (See Note 2 – Acquisitions ), the acquired ACMP business is reported within Williams Partners. For periods prior to the ACMP Acquisition, the results associated with our former equity-method investment in ACMP are reported within Other. Williams Partners Williams Partners consists of our consolidated master limited partnership, WPZ, and primarily includes gas pipeline and midstream businesses. WPZ’s gas pipeline businesses primarily consist of two interstate natural gas pipelines, which are Transcontinental Gas Pipe Line Company, LLC ( Transco ) and Northwest Pipeline LLC ( Northwest Pipeline ), and several joint venture investments in interstate and intrastate natural gas pipeline systems, including a 50 percent equity-method investment in Gulfstream Natural Gas System, L.L.C. ( Gulfstream ), and a 41 percent interest in Constitution Pipeline Company, LLC ( Constitution ) (a consolidated entity), which is under development. WPZ’s midstream businesses primarily consist of (1) natural gas gathering, treating, compression, and processing; (2) natural gas liquid (NGL) fractionation, storage, and transportation; (3) crude oil production handling and transportation; and (4) olefins production. The primary service areas are concentrated in major producing basins in Colorado, Texas, Oklahoma, Kansas, New Mexico, Wyoming, the Gulf of Mexico, Louisiana, Pennsylvania, West Virginia, New York, and Ohio which include the Barnett, Eagle Ford, Haynesville, Marcellus, Niobrara, and Utica shale plays as well as the Mid-Continent region. The midstream businesses include equity-method investments in natural gas gathering and processing assets and NGL fractionation and transportation assets, including a 62 percent equity-method investment in Utica East Ohio Midstream, LLC ( UEOM ), a 50 percent equity-method investment in the Delaware basin gas gathering system in the Mid-Continent region, a 69 percent equity-method investment in Laurel Mountain Midstream, LLC ( Laurel Mountain ), a 58 percent equity-method investment in Caiman Energy II, LLC ( Caiman II ), a 60 percent equity-method investment in Discovery Producer Services, LLC ( Discovery ), a 50 percent equity-method investment in Overland Pass Pipeline, LLC ( OPPL ), and Appalachia Midstream Services, LLC, which owns equity-method investments with an approximate average 45 percent interest in multiple gathering systems in the Marcellus Shale ( Appalachia Midstream Investments ). The midstream businesses also include our Canadian midstream operations, which are comprised of an oil sands offgas processing plant near Fort McMurray, Alberta, and an NGL/olefin fractionation facility and butylene/butane splitter facility at Redwater, Alberta. Williams NGL & Petchem Services Williams NGL & Petchem Services includes certain other domestic olefins pipeline assets and certain Canadian growth projects under development (including a propane dehydrogenation facility and a liquids extraction plant). Other Other includes other business activities that are not operating segments, as well as corporate operations. Basis of Presentation Canada Dropdown In February 2014, we contributed certain Canadian operations to Pre-merger WPZ (Canada Dropdown) for total consideration of $56 million of cash from Pre-merger WPZ (including a $31 million post-closing adjustment received in the second quarter of 2014), 25,577,521 Pre-merger WPZ Class D limited-partner units, and an increase in the capital account of its general partner to allow us to maintain our 2 percent general partner interest. In lieu of cash distributions, the Class D units received quarterly distributions of additional paid-in-kind Class D units. In October 2014, a purchase price adjustment was finalized whereby we paid $56 million in cash to Pre-merger WPZ in the fourth quarter and waived $2 million in payment of IDRs with respect to the November 2014 distribution. Consolidated master limited partnership During the fourth quarter of 2015, WPZ issued 1,790,840 common units pursuant to an equity distribution agreement between WPZ and certain banks. Considering this, as well as WPZ’s quarterly distribution of additional paid-in-kind Class B units to us, we own approximately 60 percent of the interests in WPZ, including the interests of the general partner, which are wholly owned by us, and IDRs as of December 31, 2015 . The previously described ACMP Merger and other equity issuances by WPZ had the combined net impact of increasing Noncontrolling interests in consolidated subsidiaries by $254 million , and decreasing Capital in excess of par value by $160 million and Deferred income tax liabilities by $94 million in the Consolidated Balance Sheet . WPZ is self-funding and maintains separate lines of bank credit and cash management accounts and also has a commercial paper program. (See Note 14 – Debt, Banking Arrangements, and Leases .) Cash distributions from WPZ to us, including any associated with our IDRs, occur through the normal partnership distributions from WPZ to all partners. Discontinued operations Unless indicated otherwise, the information in the Notes to Consolidated Financial Statements relates to our continuing operations. Summary of Significant Accounting Policies Principles of consolidation The consolidated financial statements include the accounts of all entities that we control and our proportionate interest in the accounts of certain ventures in which we own an undivided interest. Management’s judgment is required to evaluate whether we control an entity. Key areas of that evaluation include: • Determining whether an entity is a variable interest entity (VIE); • Determining whether we are the primary beneficiary of a VIE, including evaluating which activities of the VIE most significantly impact its economic performance and the degree of power that we and our related parties have over those activities through our variable interests; • Identifying events that require reconsideration of whether an entity is a VIE and continuously evaluating whether we are a VIE’s primary beneficiary; • Evaluating whether other owners in entities that are not VIEs are able to effectively participate in significant decisions that would be expected to be made in the ordinary course of business such that we do not have the power to control such entities. We apply the equity method of accounting to investments over which we exercise significant influence but do not control. Equity-method investment basis differences Differences between the cost of our equity-method investments and our underlying equity in the net assets of investees are accounted for as if the investees were consolidated subsidiaries. Equity earnings (losses) in the Consolidated Statement of Operations includes our allocable share of net income (loss) of investees adjusted for any depreciation and amortization, as applicable, associated with basis differences. Use of estimates 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. Significant estimates and assumptions include: • Impairment assessments of investments, property, plant, and equipment, goodwill, and other identifiable intangible assets; • Litigation-related contingencies; • Environmental remediation obligations; • Realization of deferred income tax assets; • Depreciation and/or amortization of equity-method investment basis differences; • Asset retirement obligations; • Pension and postretirement valuation variables; • Acquisition related purchase price allocations. These estimates are discussed further throughout these notes. Regulatory accounting Transco and Northwest Pipeline are regulated by the Federal Energy Regulatory Commission (FERC). Their rates, which are established by the FERC, are designed to recover the costs of providing the regulated services, and their competitive environment makes it probable that such rates can be charged and collected. Therefore, our management has determined that it is appropriate under Accounting Standards Codification (ASC) Topic 980, “Regulated Operations,” to account for and report regulatory assets and liabilities related to these operations consistent with the economic effect of the way in which their rates are established. Accounting for these operations that are regulated can differ from the accounting requirements for nonregulated operations. For example, for regulated operations, allowance for funds used during construction (AFUDC) represents the estimated cost of debt and equity funds applicable to utility plant in process of construction and is capitalized as a cost of property, plant, and equipment because it constitutes an actual cost of construction under established regulatory practices; nonregulated operations are only allowed to capitalize the cost of debt funds related to construction activities, while a component for equity is prohibited. The components of our regulatory assets and liabilities relate to the effects of deferred taxes on equity funds used during construction, asset retirement obligations, fuel cost differentials, levelized incremental depreciation, negative salvage, and pension and other postretirement benefits. Our current and noncurrent regulatory asset and liability balances for the years ended December 31, 2015 and 2014 are as follows: December 31, 2015 2014 (Millions) Current assets reported within Other current assets and deferred charges $ 84 $ 81 Noncurrent assets reported within Regulatory assets, deferred charges, and other 370 337 Total regulated assets $ 454 $ 418 Current liabilities reported within Accrued liabilities $ 4 $ 11 Noncurrent liabilities reported within Other noncurrent liabilities 434 375 Total regulated liabilities $ 438 $ 386 Cash and cash equivalents Cash and cash equivalents in the Consolidated Balance Sheet includes amounts primarily invested in funds with high-quality, short-term securities and instruments that are issued or guaranteed by the U.S. government. These have maturity dates of three months or less when acquired. Accounts receivable Accounts receivable are carried on a gross basis, with no discounting, less an allowance for doubtful accounts. We estimate the allowance for doubtful accounts based on existing economic conditions, the financial condition of our customers, and the amount and age of past due accounts. We consider receivables past due if full payment is not received by the contractual due date. Interest income related to past due accounts receivable is generally recognized at the time full payment is received or collectability is assured. Past due accounts are generally written off against the allowance for doubtful accounts only after all collection attempts have been exhausted. Inventory valuation All Inventories in the Consolidated Balance Sheet are stated at the lower of cost or market. The cost of inventories is primarily determined using the average-cost method. Property, plant, and equipment Property, plant, and equipment is recorded at cost. We base the carrying value of these assets on estimates, assumptions, and judgments relative to capitalized costs, useful lives, and salvage values. As regulated entities, Northwest Pipeline and Transco provide for depreciation using the straight-line method at FERC-prescribed rates. Depreciation for nonregulated entities is provided primarily on the straight-line method over estimated useful lives, except for certain offshore facilities that apply an accelerated depreciation method. Gains or losses from the ordinary sale or retirement of property, plant, and equipment for regulated pipelines are credited or charged to accumulated depreciation. Other gains or losses are recorded in Other (income) expense – net included in Operating income (loss) in the Consolidated Statement of Operations . Ordinary maintenance and repair costs are generally expensed as incurred. Costs of major renewals and replacements are capitalized as property, plant, and equipment. We record a liability and increase the basis in the underlying asset for the present value of each expected future asset retirement obligation (ARO) at the time the liability is initially incurred, typically when the asset is acquired or constructed. As regulated entities, Northwest Pipeline and Transco offset the depreciation of the underlying asset that is attributable to capitalized ARO cost to a regulatory asset as management expects to recover these amounts in future rates. We measure changes in the liability due to passage of time by applying an interest rate to the liability balance. This amount is recognized as an increase in the carrying amount of the liability and as a corresponding accretion expense included in Operating and maintenance expenses in the Consolidated Statement of Operations , except for regulated entities, for which the liability is offset by a regulatory asset. The regulatory asset is amortized commensurate with our collection of those costs in rates. Measurements of AROs include, as a component of future expected costs, an estimate of the price that a third party would demand, and could expect to receive, for bearing the uncertainties inherent in the obligations, sometimes referred to as a market-risk premium. Goodwill Goodwill in the Consolidated Balance Sheet represents the excess of the consideration plus the fair value of any noncontrolling interest or any previously held equity interest, over the fair value of the net assets acquired. It is not subject to amortization but is evaluated annually as of October 1 for impairment or more frequently if impairment indicators are present that would indicate it is more likely than not that the fair value of the reporting unit is less than its carrying amount. As part of the evaluation, we compare our estimate of the fair value of the reporting unit with its carrying value, including goodwill. If the carrying value of the reporting unit exceeds its fair value, a computation of the implied fair value of the goodwill is compared with its related carrying value. If the carrying value of the reporting unit goodwill exceeds the implied fair value of that goodwill, an impairment loss is recognized in the amount of the excess. Judgments and assumptions are inherent in our management’s estimates of fair value. Other intangible assets Our identifiable intangible assets are primarily related to gas gathering, processing, and fractionation contractual customer relationships. Our intangible assets are amortized on a straight-line basis over the period in which these assets contribute to our cash flows. We evaluate these assets for changes in the expected remaining useful lives and would reflect any changes prospectively through amortization over the revised remaining useful life. Impairment of property, plant, and equipment, other identifiable intangible assets, and investments We evaluate our property, plant, and equipment and other identifiable intangible assets for impairment when events or changes in circumstances indicate, in our management’s judgment, that the carrying value of such assets may not be recoverable. When an indicator of impairment has occurred, we compare our management’s estimate of undiscounted future cash flows attributable to the assets to the carrying value of the assets to determine whether an impairment has occurred and we may apply a probability-weighted approach to consider the likelihood of different cash flow assumptions and possible outcomes including selling in the near term or holding for the remaining estimated useful life. If an impairment of the carrying value has occurred, we determine the amount of the impairment recognized in the financial statements by estimating the fair value of the assets and recording a loss for the amount that the carrying value exceeds the estimated fair value. This evaluation is performed at the lowest level for which separately identifiable cash flows exist. For assets identified to be disposed of in the future and considered held for sale, we compare the carrying value to the estimated fair value less the cost to sell to determine if recognition of an impairment is required. Until the assets are disposed of, the estimated fair value, which includes estimated cash flows from operations until the assumed date of sale, is recalculated when related events or circumstances change. We evaluate our investments for impairment when events or changes in circumstances indicate, in our management’s judgment, that the carrying value of such investments may have experienced an other-than-temporary decline in value. When evidence of loss in value has occurred, we compare our estimate of fair value of the investment to the carrying value of the investment to determine whether an impairment has occurred. If the estimated fair value is less than the carrying value and we consider the decline in value to be other-than-temporary, the excess of the carrying value over the fair value is recognized in the consolidated financial statements as an impairment charge. Judgments and assumptions are inherent in our management’s estimate of undiscounted future cash flows and an asset’s or investment’s fair value. Additionally, judgment is used to determine the probability of sale with respect to assets considered for disposal. Contingent liabilities We record liabilities for estimated loss contingencies, including environmental matters, when we assess that a loss is probable and the amount of the loss can be reasonably estimated. These liabilities are calculated based upon our assumptions and estimates with respect to the likelihood or amount of loss and upon advice of legal counsel, engineers, or other third parties regarding the probable outcomes of the matters. These calculations are made without consideration of any potential recovery from third parties. We recognize insurance recoveries or reimbursements from others when realizable. Revisions to these liabilities are generally reflected in income when new or different facts or information become known or circumstances change that affect the previous assumptions or estimates. Cash flows from revolving credit facilities and commercial paper program Proceeds and payments related to borrowings under our credit facilities are reflected in the financing activities in the Consolidated Statement of Cash Flows on a gross basis. Proceeds and payments related to borrowings under our commercial paper program are reflected in the financing activities in the Consolidated Statement of Cash Flows on a net basis, as the outstanding notes generally have maturity dates less than three months from the date of issuance. (See Note 14 – Debt, Banking Arrangements, and Leases .) Treasury stock Treasury stock purchases are accounted for under the cost method whereby the entire cost of the acquired stock is recorded as Treasury stock in the Consolidated Balance Sheet . Gains and losses on the subsequent reissuance of shares are credited or charged to Capital in excess of par value in the Consolidated Balance Sheet using the average-cost method. Derivative instruments and hedging activities We may utilize derivatives to manage a portion of our commodity price risk. These instruments consist primarily of swaps, futures, and forward contracts involving short- and long-term purchases and sales of physical energy commodities. We report the fair value of derivatives, except those for which the normal purchases and normal sales exception has been elected, in Other current assets and deferred charges ; Regulatory assets, deferred charges, and other ; Accrued liabilities ; or Other noncurrent liabilities in the Consolidated Balance Sheet . We determine the current and noncurrent classification based on the timing of expected future cash flows of individual trades. We report these amounts on a gross basis. Additionally, we report cash collateral receivables and payables with our counterparties on a gross basis. (See Note 17 – Fair Value Measurements, Guarantees, and Concentration of Credit Risk .) The accounting for the changes in fair value of a commodity derivative can be summarized as follows: Derivative Treatment Accounting Method Normal purchases and normal sales exception Accrual accounting Designated in a qualifying hedging relationship Hedge accounting All other derivatives Mark-to-market accounting We may elect the normal purchases and normal sales exception for certain short- and long-term purchases and sales of physical energy commodities. Under accrual accounting, any change in the fair value of these derivatives is not reflected on the balance sheet after the initial election of the exception. We may also designate a hedging relationship for certain commodity derivatives. For a derivative to qualify for designation in a hedging relationship, it must meet specific criteria and we must maintain appropriate documentation. We establish hedging relationships pursuant to our risk management policies. We evaluate the hedging relationships at the inception of the hedge and on an ongoing basis to determine whether the hedging relationship is, and is expected to remain, highly effective in achieving offsetting changes in fair value or cash flows attributable to the underlying risk being hedged. We also regularly assess whether the hedged forecasted transaction is probable of occurring. If a derivative ceases to be or is no longer expected to be highly effective, or if we believe the likelihood of occurrence of the hedged forecasted transaction is no longer probable, hedge accounting is discontinued prospectively, and future changes in the fair value of the derivative are recognized currently in Product sales or Product costs in the Consolidated Statement of Operations . For commodity derivatives designated as a cash flow hedge, the effective portion of the change in fair value of the derivative is reported in Accumulated other comprehensive income (loss) (AOCI) in the Consolidated Balance Sheet and reclassified into earnings in the period in which the hedged item affects earnings. Any ineffective portion of the derivative’s change in fair value is recognized currently in Product sales or Product costs in the Consolidated Statement of Operations . Gains or losses deferred in AOCI associated with terminated derivatives, derivatives that cease to be highly effective hedges, derivatives for which the forecasted transaction is reasonably possible but no longer probable of occurring, and cash flow hedges that have been otherwise discontinued remain in AOCI until the hedged item affects earnings. If it becomes probable that the forecasted transaction designated as the hedged item in a cash flow hedge will not occur, any gain or loss deferred in AOCI is recognized in Product sales or Product costs in the Consolidated Statement of Operations at that time. The change in likelihood of a forecasted transaction is a judgmental decision that includes qualitative assessments made by management. For commodity derivatives that are not designated in a hedging relationship, and for which we have not elected the normal purchases and normal sales exception, we report changes in fair value currently in Product sales or Product costs in the Consolidated Statement of Operations . Certain gains and losses on derivative instruments included in the Consolidated Statement of Operations are netted together to a single net gain or loss, while other gains and losses are reported on a gross basis. Gains and losses recorded on a net basis include unrealized gains and losses on all derivatives that are not designated as hedges and for which we have not elected the normal purchases and normal sales exception. Realized gains and losses on derivatives that require physical delivery, as well as natural gas derivatives for NGL processing activities and which are not held for trading purposes nor were entered into as a pre-contemplated buy/sell arrangement, are recorded on a gross basis. Revenue recognition Revenues As a result of the ratemaking process, certain revenues collected by us may be subject to refunds upon the issuance of final orders by the FERC in pending rate proceedings. We record estimates of rate refund liabilities considering our and other third-party regulatory proceedings, advice of counsel, and other risks. Service revenues Revenues from our gas pipeline businesses include se

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Acquisitions [Text Block]	Note 2 – Acquisitions ACMP On December 20, 2012, we purchased approximately 24 percent of ACMP’s outstanding limited partnership units and 50 percent of the ACMP general partner 2 percent interest which includes IDRs for approximately $2.19 billion in cash, including transaction costs. We accounted for these acquired interests as equity-method investments. On July 1, 2014, we acquired control of ACMP (ACMP Acquisition) through the acquisition of an additional 26 percent of ACMP’s outstanding limited partnership units and the remaining 50 percent interest in the general partner for $5.995 billion in cash. The acquisition was funded through the issuance of equity (see Note 15 – Stockholders' Equity ) and debt (see Note 14 – Debt, Banking Arrangements, and Leases ), credit facility borrowings, and cash on hand. At the time of acquisition, ACMP owned, operated, developed, and acquired natural gas gathering systems and other midstream energy assets. The purpose of the acquisition was to enhance our position in the Marcellus and Utica shale plays, provide additional diversity via the Eagle Ford, Haynesville, Barnett, Mid-Continent, and Niobrara areas, and to fortify our stable, fee-based business model and support our dividend growth strategy. Our basis in ACMP reflects business combination accounting, which, among other things, requires identifiable assets acquired and liabilities assumed to be measured at their acquisition-date fair values. Prior to the ACMP Acquisition we accounted for our investment in ACMP using the equity method. The acquisition-date fair value of our equity-method investment in ACMP was $4.6 billion . As a result of remeasuring our equity-method investment to fair value, for the year ended December 31, 2014 we recognized a $2.5 billion noncash gain within the Gain on remeasurement of equity-method investment line item in the Consolidated Statement of Operations . The valuation techniques used to measure the acquisition-date fair value of the ACMP Acquisition, including our previous equity-method investment in ACMP, consisted of valuing the limited partner units and general partner interest separately. The limited partner units, consisting of common and Class B units, were valued based on ACMP’s closing common unit price at July 1, 2014. The general partner interest, including IDRs, was valued on a noncontrolling basis using an income approach based on a discounted cash flow analysis and a market comparison analysis based on comparable guideline companies and an implied fair value from our purchase. The following table presents the allocation of the acquisition-date fair value of the major classes of the assets acquired, which are presented in the Williams Partners segment, liabilities assumed, and noncontrolling interest at July 1, 2014. The fair value of accounts receivable acquired equaled contractual amounts receivable. Changes to the preliminary allocation disclosed in Exhibit 99.1 of our Form 8-K dated May 6, 2015, which were recorded in the first quarter of 2015, reflect an increase of $150 million in Property, plant, and equipment and $25 million in Goodwill , and a decrease of $168 million in Other intangible assets and $7 million in Investments . These adjustments during the measurement period were not considered significant to require retrospective revisions of our financial statements. (Millions) Accounts receivable $ 168 Other current assets 63 Investments 5,865 Property, plant, and equipment 7,165 Goodwill 499 Other intangible assets 8,841 Current liabilities (408 ) Debt (4,052 ) Other noncurrent liabilities (9 ) Noncontrolling interest in ACMP’s subsidiaries (958 ) Noncontrolling interest in ACMP (6,544 ) Other intangible assets recognized in the acquisition are related to contractual customer relationships from gas gathering agreements with our customers. The basis for determining the value of these intangible assets was estimated future net cash flows to be derived from acquired contractual customer relationships discounted using a risk-adjusted discount rate. These intangible assets are being amortized on a straight-line basis over 30 years during which contractual customer relationships are expected to contribute to our cash flows. As estimated at the time of acquisition, approximately 56 percent of the expected future revenues from these contractual customer relationships were impacted by our ability and intent to renew or renegotiate existing customer contracts. We expense costs incurred to renew or extend the terms of our gas gathering, processing, and fractionation contracts with customers. Based on the estimated future revenues during the current contract periods (as estimated at the time of acquisition), the weighted-average periods to the next renewal or extension of the existing customer contracts was approximately 17 years . The noncash adjustment to record the fair value of the noncontrolling interest in ACMP was determined based on the common units and ACMP’s closing common unit price at July 1, 2014. The following unaudited pro forma Revenues and Net income attributable to The Williams Companies, Inc. for the years ended December 31, 2014 and 2013, are presented as if the ACMP Acquisition had been completed on January 1, 2013. These pro forma amounts are not necessarily indicative of what the actual results would have been if the acquisition had in fact occurred on the date or for the periods indicated, nor do they purport to project Revenues or Net income attributable to The Williams Companies, Inc. for any future periods or as of any date. These amounts do not give effect to any potential cost savings, operating synergies, or revenue enhancements to result from the transactions or the potential costs to achieve these cost savings, operating synergies, and revenue enhancements. December 31, 2014 2013 (Millions) Revenues $ 8,181 $ 7,906 Net income attributable to The Williams Companies, Inc. $ 622 $ 356 Significant adjustments to pro forma Net income attributable to The Williams Companies, Inc. include the removal of the previously described $2.5 billion gain on remeasurement of equity-method investment, and include additional depreciation and amortization expense associated with reflecting the acquired investments, property, plant, and equipment, and other intangible assets at fair value. The adjustments assume estimated useful lives of 30 years . Other significant adjustments to pro forma Net income attributable to The Williams Companies, Inc. include interest expense related to debt financing associated with the acquisition as well as Net income attributable to noncontrolling interests . During the year ended December 31, 2014, ACMP contributed Revenues of $781 million and Net income attributable to The Williams Companies, Inc. of $165 million . Costs related to this acquisition were $16 million in 2014 and are reported within our Williams Partners segment and included in Selling, general, and administrative expenses in our Consolidated Statement of Operations . Direct transaction costs associated with financing commitments were $9 million in 2014 and reported within Interest incurred in our Consolidated Statement of Operations . Equity earnings (losses) within our Consolidated Statement of Operations in 2014 includes $19 million of equity losses associated with certain compensation-related costs at ACMP that were triggered by the acquisition. Eagle Ford Gathering System In May 2015, WPZ acquired a gathering system comprised of approximately 140 miles of pipeline and a sour gas compression facility in the Eagle Ford shale for $112 million . The acquisition was accounted for as a business combination, and the allocation of the acquisition-date fair value of the major classes of assets acquired includes $80 million of Property, plant, and equipment, at cost and $32 million of Other intangible assets – net of accumulated amortization in the Consolidated Balance Sheet . Changes to the preliminary allocation disclosed in the second quarter of 2015 reflect an increase of $20 million in Property, plant, and equipment, at cost , and a decrease of $20 million in Other intangible assets – net of accumulated amortization . UEOM Equity-Method Investment In June 2015, WPZ acquired an approximate 13 percent additional interest in its equity-method investment, UEOM, for $357 million . Following the acquisition WPZ owns approximately 62 percent of UEOM. However, WPZ continues to account for this as an equity-method investment because WPZ does not control UEOM due to the significant participatory rights of its partner. In connection with the acquisition of the additional interest, we have agreed to waive approximately $2 million of our WPZ IDR payments each quarter through 2017.

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2015
Variable Interest Entity Disclosures [Abstract]
Variable Interest Entities [Text Block]	Note 3 – Variable Interest Entities As of December 31, 2015 , we consolidate the following VIEs: Gulfstar One WPZ owns a 51 percent interest in Gulfstar One LLC (Gulfstar One), a subsidiary that, due to certain risk-sharing provisions in its customer contracts, is a VIE. Gulfstar One includes a proprietary floating-production system, Gulfstar FPS, and associated pipelines which provide production handling and gathering services for the Tubular Bells oil and gas discovery in the eastern deepwater Gulf of Mexico. WPZ is the primary beneficiary because it has the power to direct the activities that most significantly impact Gulfstar One’s economic performance. Construction of an expansion project is underway that will provide production handling and gathering services for the Gunflint oil and gas discovery in the eastern deepwater Gulf of Mexico. The expansion project is expected to be in service in the first half of 2016. The current estimate of the total remaining construction cost for the expansion project is approximately $130 million , which is expected to be funded with revenues received from customers and capital contributions from WPZ and the other equity partner on a proportional basis. Constitution WPZ owns a 41 percent interest in Constitution, a subsidiary that, due to shipper fixed-payment commitments under its long-term firm transportation contracts, is a VIE. WPZ is the primary beneficiary because it has the power to direct the activities that most significantly impact Constitution’s economic performance. WPZ, as construction manager for Constitution, is responsible for constructing the proposed pipeline connecting its gathering system in Susquehanna County, Pennsylvania, to the Iroquois Gas Transmission and the Tennessee Gas Pipeline systems. WPZ plans to place the project in service in the fourth quarter of 2016, assuming timely receipt of all necessary regulatory approvals, and estimates the total remaining cost of the project to be approximately $571 million , which is expected to be funded with capital contributions from WPZ and the other equity partners on a proportional basis. Cardinal WPZ owns a 66 percent interest in Cardinal Gas Services, L.L.C (Cardinal), a subsidiary that provides gathering services for the Utica region and is a VIE due to certain risks shared with customers. WPZ is the primary beneficiary because it has the power to direct the activities that most significantly impact Cardinal’s economic performance. Future expansion activity is expected to be funded with capital contributions from WPZ and the other equity partner on a proportional basis. Jackalope WPZ owns a 50 percent interest in Jackalope Gas Gathering Services, L.L.C (Jackalope), a subsidiary that provides gathering and processing services for the Powder River basin and is a VIE due to certain risks shared with customers. WPZ is the primary beneficiary because it has the power to direct the activities that most significantly impact Jackalope’s economic performance. Future expansion activity is expected to be funded with capital contributions from WPZ and the other equity partner on a proportional basis. The following table presents amounts included in our Consolidated Balance Sheet that are for the use or obligation of our consolidated VIEs. December 31, 2015 2014 Classification (Millions) Assets (liabilities): Cash and cash equivalents $ 70 $ 113 Cash and cash equivalents Accounts receivable 71 52 Accounts and notes receivable – net, Trade and other Other current assets 2 3 Other current assets and deferred charges Property, plant, and equipment – net 3,000 2,794 Property, plant, and equipment – net Goodwill 47 103 Goodwill Other intangible assets – net 1,436 1,493 Other intangible assets – net of accumulated amortization Other noncurrent assets — 14 Regulatory assets, deferred charges, and other Accounts payable (59 ) (48 ) Accounts payable Accrued liabilities (14 ) (36 ) Accrued liabilities Current deferred revenue (62 ) (45 ) Accrued liabilities Noncurrent deferred income taxes — (13 ) Deferred income tax liabilities Asset retirement obligation (93 ) (94 ) Other noncurrent liabilities Noncurrent deferred revenue associated with customer advance payments (331 ) (395 ) Other noncurrent liabilities

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions Disclosure [Text Block]	Note 4 – Related Party Transactions Transactions with Equity-Method Investees We have purchases from our equity-method investees included in Product costs in the Consolidated Statement of Operations of $187 million , $197 million , and $161 million for the years ended 2015, 2014, and 2013, respectively. We have $12 million and $13 million included in Accounts payable in the Consolidated Balance Sheet with our equity-method investees at December 31, 2015 and 2014, respectively. WPZ has operating agreements with certain equity-method investees. These operating agreements typically provide for reimbursement or payment to WPZ for certain direct operational payroll and employee benefit costs, materials, supplies, and other charges and also for management services. We supplied a portion of these services, primarily those related to employees since WPZ does not have any employees, to certain equity-method investees. The total gross charges to equity-method investees for these fees included in the Consolidated Statement of Operations are $64 million , $65 million , and $67 million for the years ended 2015, 2014, and 2013, respectively. Board of Directors A member of our Board of Directors, who was elected in 2013, is also the current chairman, president, and chief executive officer of an energy services company that is a customer of ours. We recorded $111 million , $115 million , and $131 million in Service revenues in the Consolidated Statement of Operations from this company for transportation and storage of natural gas for the years ended December 31, 2015, 2014, and 2013, respectively.

Investing Activities

Investing Activities	12 Months Ended
	Dec. 31, 2015
Investments [Abstract]
Investing Activities [Text Block]	Note 5 – Investing Activities Gain on remeasurement of equity-method investment in the Consolidated Statement of Operations We recognized a $2.544 billion noncash gain in 2014 associated with the ACMP Acquisition. (See Note 2 – Acquisitions .) Impairment of equity-method investments in the Consolidated Statement of Operations During the third quarter of 2015, we recognized other-than-temporary impairment charges of $458 million and $3 million related to WPZ’s equity-method investments in the Delaware basin gas gathering system and certain of the Appalachia Midstream Investments, respectively. During the fourth quarter of 2015, we recognized additional impairment charges for these investments of $45 million and $559 million , respectively, as well as impairment charges of $241 million and $45 million associated with WPZ’s equity-method investments in UEOM and Laurel Mountain, respectively. (See Note 17 – Fair Value Measurements, Guarantees, and Concentration of Credit Risk .) These charges are reported within the Williams Partners segment. Equity earnings (losses) in the Consolidated Statement of Operations Equity earnings (losses) in 2015 includes a loss of $19 million associated with WPZ’s share of underlying property impairments at certain of the Appalachia Midstream Investments. This loss is reported within the Williams Partners segment. Equity earnings (losses) in 2014 includes: • Write-offs of capitalized project development costs on our discontinued investments in Bluegrass Pipeline of $67 million and Moss Lake of $4 million ; • a $7 million equity loss recognized from our interest in ACMP that was accounted for under the equity-method of accounting for the first six months of the year, including $19 million of equity losses associated with certain compensation-related costs at ACMP that were triggered by the acquisition and $30 million noncash amortization of the difference between the cost of our investment and our underlying share of the net assets for the first six months of the year. Equity earnings (losses) in 2013 includes $93 million of equity earnings recognized from our interest in ACMP, acquired at the end of 2012, that was accounted for under the equity-method of accounting, partially offset by $63 million noncash amortization of the difference between the cost of our investment and our underlying share of the net assets. Other investing income (loss) – net in the Consolidated Statement of Operations Other investing income (loss) – net includes $27 million , $41 million , and $50 million of interest income for 2015, 2014 and 2013, respectively, associated with a receivable related to the sale of certain former Venezuela assets. Due to changes in circumstances that led to late payments and increased uncertainty regarding the recovery of the receivable, we began accounting for the receivable under a cost recovery model in first quarter 2015. Subsequently, we received payments greater than the remaining carrying amount of the receivable, which resulted in the recognition of interest income. Other investing income (loss) – net in 2013 also includes a $31 million gain resulting from ACMP’s equity issuances during 2013. These equity issuances resulted in the dilution of our limited partner interest at that time from approximately 24 percent to 23 percent , which is accounted for as though we sold a portion of our investment. Investments in the Consolidated Balance Sheet December 31, 2015 2014 (Millions) Equity-method investments: Appalachia Midstream Investments (1) $ 2,464 $ 3,033 UEOM — 62% (2) 1,525 1,411 Delaware basin gas gathering system — 50% 977 1,478 Discovery — 60% 602 602 OPPL – 50% 445 453 Caiman II — 58% 418 432 Laurel Mountain — 69% 391 459 Gulfstream — 50% 293 317 Other 221 215 $ 7,336 $ 8,400 ___________ (1) Includes equity-method investments in multiple gathering systems in the Marcellus Shale with an approximate average 45 percent interest. (2) WPZ acquired an approximate 13 percent additional interest in UEOM in 2015. (See Note 2 – Acquisitions ). We have differences between the carrying value of our equity-method investments and the underlying equity in the net assets of the investees of $2.4 billion at December 31, 2015 and $3.7 billion at December 31, 2014. These differences primarily relate to our investments in Appalachian Midstream Investments, Delaware basin gas gathering system, and UEOM resulting from property, plant, and equipment, as well as customer-based intangible assets and goodwill. Purchases of and contributions to equity-method investments in the Consolidated Statement of Cash Flows We generally fund our portion of significant expansion or development projects of these investees through additional capital contributions. These transactions increased the carrying value of our investments and included: Years Ended December 31, 2015 2014 2013 (Millions) UEOM (1) $ 357 $ 57 $ — Appalachia Midstream Investments 93 84 — Delaware basin gas gathering system 57 20 — Discovery 35 106 193 Caiman II — 175 192 Other 53 40 70 $ 595 $ 482 $ 455 ___________ (1) 2015 includes additional interest in UEOM acquired by WPZ. (See Note 2 – Acquisitions .) Dividends and distributions The organizational documents of entities in which we have an equity-method interest generally require distribution of available cash to members on at least a quarterly basis. These transactions reduced the carrying value of our investments and included: Years Ended December 31, 2015 2014 2013 (Millions) Appalachia Midstream Investments $ 219 $ 130 $ — Discovery 116 36 12 Gulfstream 88 81 81 OPPL 45 27 27 UEOM 42 — — Caiman II 33 13 — Delaware basin gas gathering system 33 — — Laurel Mountain 31 39 — Access Midstream Investments — 64 93 Other 26 50 34 $ 633 $ 440 $ 247 In addition, on September 24, 2015, WPZ received a special distribution of $396 million from Gulfstream reflecting its proportional share of the proceeds from new debt issued by Gulfstream. The new debt was issued to refinance Gulfstream’s debt maturities. Subsequently, WPZ contributed $248 million to Gulfstream for its proportional share of amounts necessary to fund debt maturities of $500 million due on November 1, 2015. WPZ also expects to contribute its proportional share of amounts necessary to fund debt maturities of $300 million due on June 1, 2016, as reflected by the accrued liability of $149 million in Accrued liabilities in the Consolidated Balance Sheet at December 31, 2015. Summarized Financial Position and Results of Operations of All Equity-Method Investments December 31, 2015 2014 (Millions) Assets (liabilities): Current assets $ 773 $ 599 Noncurrent assets 9,549 9,135 Current liabilities (633 ) (850 ) Noncurrent liabilities (1,450 ) (954 ) Years Ended December 31, 2015 2014 2013 (Millions) Gross revenue $ 1,707 $ 1,623 $ 2,406 Operating income 690 534 699 Net income 611 460 627

Other Income and Expenses

Other Income and Expenses	12 Months Ended
	Dec. 31, 2015
Other Income and Expenses [Abstract]
Other Income and Expense [Text Block]	Note 6 – Other Income and Expenses The following table presents certain gains or losses reflected in Other (income) expense – net within Costs and expenses in our Consolidated Statement of Operations : Years Ended December 31, 2015 2014 2013 (Millions) Williams Partners Impairment of certain assets (See Note 17) $ 145 $ 52 $ — Amortization of regulatory assets associated with asset retirement obligations 33 33 30 Contingency gain settlement (1) — (154 ) — Net gain related to partial acreage dedication release — (12 ) — Loss related to sale of certain assets — 10 — Write-off of the Eminence abandonment regulatory asset not recoverable through rates — (3 ) 12 Insurance recoveries associated with the Eminence abandonment — — (16 ) Loss associated with a producer claim — — 25 Williams NGL & Petchem Services Impairment of certain assets (See Note 17) 64 — 20 ________________ (1) In November 2014, we settled a claim arising from the resolution of a contingent gain related to claims associated with the purchase of a business in a prior period. Pursuant to the settlement, we received $154 million in cash, all of which was recognized as a gain in the fourth quarter of 2014. Geismar Incident On June 13, 2013, an explosion and fire occurred at Williams Partners’ Geismar olefins plant. The incident rendered the facility temporarily inoperable (Geismar Incident). In 2015, 2014, and 2013, we received $126 million , $246 million , and $50 million , respectively, of insurance recoveries related to the Geismar Incident. These amounts are reported within the Williams Partners segment and reflected as gains in Net insurance recoveries – Geismar Incident in our Consolidated Statement of Operations . Also, in 2014 and 2013, we incurred $14 million and $10 million , respectively, of covered insurable expenses in excess of our retentions (deductibles) also included in Net insurance recoveries – Geismar Incident in the Consolidated Statement of Operations and we expensed $13 million within the Williams Partners segment in 2013 of costs under our insurance deductibles reported in Operating and maintenance expenses in the Consolidated Statement of Operations . ACMP Acquisition & Merger Certain ACMP Acquisition and ACMP Merger costs included in Selling, general, and administrative expenses , Operating and maintenance expenses , and Interest incurred in the Consolidated Statement of Operations are as follows: • Selling, general, and administrative expenses includes $26 million in 2015 and $27 million in 2014 (including $16 million of ACMP Acquisition costs) primarily related to professional advisory fees associated with the ACMP Acquisition and ACMP Merger within the Williams Partners segment. • Selling, general, and administrative expenses includes $9 million in 2015 and $15 million in 2014 of related employee transition costs from the ACMP Merger within the Williams Partners segment and $32 million in 2015 and $10 million in 2014 of general corporate expenses associated with integration and realignment of resources within the Other segment. • Operating and maintenance expenses includes $12 million in 2015 and $15 million in 2014 of transition costs from the ACMP Merger within the Williams Partners segment. • Interest incurred includes transaction-related financing costs of $2 million in 2015 from the ACMP Merger and $9 million in 2014 from the ACMP Acquisition. Additional Items Certain items included in Service revenues , Product costs , Selling, general, and administrative expenses and Other income (expense) – net below Operating income (loss) in the Consolidated Statement of Operations are as follows: • Service revenues includes $239 million recognized in the fourth quarter of 2015 and $167 million recognized in the fourth quarter of 2014 from minimum volume commitment fees within the Williams Partners segment. • Product costs includes $6 million in 2015 and $27 million in 2014 of inventory adjustments within the Williams Partners segment. • Selling, general, and administrative expenses includes $30 million in 2015 of costs associated with our evaluation of strategic alternatives within the Other segment. • Selling, general, and administrative expenses includes $18 million in 2014 of project development costs related to the Bluegrass Pipeline reported within the Williams NGL & Petchem Services segment. • Other income (expense) – net below Operating income (loss) includes $95 million , $44 million , and $22 million for equity AFUDC for 2015, 2014, and 2013, respectively. Equity AFUDC increased during 2015 due to the increase in spending on various Transco expansion projects and Constitution. • Other income (expense) – net below Operating income (loss) includes a $14 million gain in 2015 resulting from the early retirement of certain debt within the Williams Partners segment.

Provision (Benefit) for Income

Provision (Benefit) for Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Provision (Benefit) for Income Taxes [Text Block]	Note 7 – Provision (Benefit) for Income Taxes The Provision (benefit) for income taxes includes: Years Ended December 31, 2015 2014 2013 (Millions) Current: Federal $ — $ (9 ) $ (17 ) State (7 ) 2 7 Foreign (55 ) 10 (13 ) (62 ) 3 (23 ) Deferred: Federal (317 ) 1,108 348 State (25 ) 119 40 Foreign 5 19 36 (337 ) 1,246 424 Provision (benefit) for income taxes $ (399 ) $ 1,249 $ 401 Reconciliations from the Provision (benefit) at statutory rate to recorded Provision (benefit) for income taxes are as follows: Years Ended December 31, 2015 2014 2013 (Millions) Provision (benefit) at statutory rate $ (600 ) $ 1,255 $ 378 Increases (decreases) in taxes resulting from: Impact of nontaxable noncontrolling interests 263 (75 ) (78 ) State income taxes (net of federal benefit) (21 ) 82 26 Foreign operations – net 8 (11 ) (32 ) Taxes on undistributed earnings of foreign subsidiaries – net — (37 ) 99 Translation adjustment of certain unrecognized tax benefits (71 ) — — Other – net 22 35 8 Provision (benefit) for income taxes $ (399 ) $ 1,249 $ 401 Income (loss) from continuing operations before income taxes includes $20 million , $102 million , and $119 million of foreign income in 2015 , 2014 , and 2013 , respectively. The 2015 federal and state income tax provisions include the tax effect of a $2.7 billion impairment loss associated with certain goodwill, equity-method investments, and other assets. (See Note 17 – Fair Value Measurements, Guarantees, and Concentration of Credit Risk ). The Translation adjustment of certain unrecognized tax benefits in 2015 reflects the impact of changes in foreign currency exchange rates on the remeasurement of a foreign currency denominated unrecognized tax benefit, including associated penalties and interest. The 2014 federal and state income tax provisions include the tax effect of a $2.5 billion gain associated with remeasuring our equity-method investment to fair value as a result of the ACMP Acquisition. (See Note 2 – Acquisitions ). On October 30, 2013, WPZ announced its intent to pursue an agreement to acquire certain of our Canadian operations. As a result, we no longer considered the undistributed earnings from these foreign operations to be permanently reinvested and thus recognized $99 million of deferred income tax expense in continuing operations and $24 million of deferred income tax benefit in AOCI during 2013. Taxes on undistributed earnings of foreign subsidiaries – net decreased in 2014 due to revisions of our estimate of the undistributed earnings, partially offset by an increase of tax expense, which decreased our share of the foreign tax credit due to the Canada Dropdown. During the course of audits of our business by domestic and foreign tax authorities, we frequently face challenges regarding the amount of taxes due. These challenges include questions regarding the timing and amount of deductions and the allocation of income among various tax jurisdictions. In evaluating the liability associated with our various filing positions, we apply the two-step process of recognition and measurement. In association with this liability, we record an estimate of related interest and tax exposure as a component of our tax provision. The impact of this accrual is included within Other – net in our reconciliation of the Provision (benefit) at statutory rate to recorded Provision (benefit) for income taxes . Significant components of Deferred income tax liabilities and Deferred income tax assets are as follows: December 31, 2015 2014 (Millions) Deferred income tax liabilities: Property, plant, and equipment $ 4 $ 4 Investments 5,272 5,472 Other 15 10 Total deferred income tax liabilities 5,291 5,486 Deferred income tax assets: Accrued liabilities 150 178 Minimum tax credits 139 137 Foreign tax credit 193 251 Federal loss carryovers 485 134 State losses and credits 296 250 Other 42 97 Total deferred income tax assets 1,305 1,047 Less valuation allowance 190 206 Net deferred income tax assets 1,115 841 Overall net deferred income tax liabilities $ 4,176 $ 4,645 The valuation allowance at December 31, 2015 and 2014 serves to reduce the available deferred income tax assets to an amount that will, more likely than not, be realized. We consider all available positive and negative evidence, including projected future taxable income, and have determined that a portion of our deferred income tax assets related to State losses and credits may not be realized. The change in Valuation allowance is due to this evaluation. The amounts presented in the table above are, with respect to state items, before any federal benefit. The change from prior year for the State losses and credits is primarily due to increases in losses and credits generated in the current and prior years less losses and/or credits utilized in the current year. We have loss and credit carryovers in multiple state taxing jurisdictions. These attributes generally expire between 2016 and 2035 with some carryovers having indefinite carryforward periods. The federal tax Minimum tax credits of $139 million currently has no expiration date. Foreign tax credit of $139 million is expected to be utilized prior to expiration in 2025. The remaining Foreign tax credit represents unrealized foreign tax credit that will be allocated to us in the future when deferred income tax liabilities associated with temporary differences on foreign assets and liabilities become current income tax liabilities in the foreign jurisdiction. Federal net operating loss carryovers and charitable contribution carryovers of $1.5 billion at the end of 2015 are expected to be utilized by us prior to expiration between 2018 and 2035. Employee share-based compensation attributable to the exercise of stock options and vesting of restricted stock is deductible by us for tax purposes. To the extent these tax deductions exceed the previously accrued deferred income tax benefit for these items, the additional tax benefit is not recognized until the deduction reduces current income taxes payable. Since the additional tax benefit does not reduce our current income taxes payable for 2015 and 2014, these tax benefits are not included in our Federal loss carryovers deferred income tax assets. The additional tax benefits deductible for tax purposes but not included in our Federal loss carryovers deferred income tax assets were $23 million each for 2015 and 2014 . Cash refunds for income taxes (net of payments and discontinued operations) were $136 million and $50 million in 2015 and 2013, respectively. Cash payments for income taxes (net of refunds) in 2014 were $29 million . As of December 31, 2015 , we had approximately $55 million of unrecognized tax benefits. If recognized, income tax expense would be reduced by $51 million , including the effect of these changes on other tax attributes, with state income tax amounts included net of federal tax effect. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: 2015 2014 (Millions) Balance at beginning of period $ 89 $ 66 Additions based on tax positions related to the current year — 11 Additions for tax positions of prior years 2 12 Reductions for tax positions of prior years — — Settlement with taxing authorities — — Changes due to currency translation (36 ) — Balance at end of period $ 55 $ 89 We recognize related interest and penalties as a component of Provision (benefit) for income taxes . Total interest and penalties recognized as part of income tax provision were benefits of $22 million for 2015, including a $35 million benefit due to currency fluctuation, and expense of $8 million and $9 million for 2014 and 2013 , respectively. Approximately $2 million and $24 million of interest and penalties primarily relating to uncertain tax positions have been accrued as of December 31, 2015 and 2014 , respectively. Changes due to currency translation in 2015 reflects the unrecognized tax benefit portion of the previously described impact of changes in foreign currency exchange rates on the remeasurement of a foreign currency denominated balance. During the next 12 months, we do not expect ultimate resolution of any unrecognized tax benefit associated with domestic or international matters to have a material impact on our unrecognized tax benefit position. Consolidated U.S Federal income tax returns are open to IRS examination for years after 2010. As of December 31, 2015, examinations of tax returns for 2011 through 2013 are currently in process. We do not expect material changes in our financial position resulting from these examinations. The statute of limitations for most states expires one year after expiration of the IRS statute. Generally, tax returns for our Canadian entities are open to audit for tax years after 2010. On September 13, 2013, the IRS issued final regulations providing guidance on the treatment of amounts paid to acquire, produce, or improve tangible property. On August 18, 2014, the IRS issued final regulations providing guidance on the dispositions of such property. The implementation date for these regulations was January 1, 2014. The IRS is expected to issue additional procedural guidance regarding how the requirements may be implemented for the gas transmission and distribution industry. Pending the issuance of this additional procedural guidance from the IRS, we cannot at this time estimate the impact of implementing the regulations for our gas transmission business, although we anticipate that it will result in an immaterial balance sheet only impact.

Earnings (Loss) Per Common Shar

Earnings (Loss) Per Common Share from Continuing Operations	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Common Share from Continuing Operations [Text Block]	Note 8 – Earnings (Loss) Per Common Share from Continuing Operations Years Ended December 31, 2015 2014 2013 (Dollars in millions, except per-share amounts; shares in thousands) Income (loss) from continuing operations attributable to The Williams Companies, Inc. available to common stockholders for basic and diluted earnings (loss) per common share $ (571 ) $ 2,110 $ 441 Basic weighted-average shares 749,271 719,325 682,948 Effect of dilutive securities: Nonvested restricted stock units — 2,234 1,995 Stock options — 2,064 2,149 Convertible debentures — 18 93 Diluted weighted-average shares (1) 749,271 723,641 687,185 Earnings (loss) per common share from continuing operations: Basic $ (.76 ) $ 2.93 $ 0.65 Diluted $ (.76 ) $ 2.91 $ 0.64 (1) For the year ended December 31, 2015, 1.7 million weighted-average nonvested restricted stock units and 1.5 million weighted-average stock options have been excluded from the computation of diluted earnings (loss) per common share as their inclusion would be antidilutive due to our loss from continuing operations attributable to The Williams Companies, Inc.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Pension and Other Postretirement Benefits Disclosure [Text Block]	Note 9 – Employee Benefit Plans We have noncontributory defined benefit pension plans in which all eligible employees participate. Currently, eligible employees earn benefits primarily based on a cash balance formula. Various other formulas, as defined in the plan documents, are utilized to calculate the retirement benefits for plan participants not covered by the cash balance formula. At the time of retirement, participants may elect, to the extent they are eligible for the various options, to receive annuity payments, a lump sum payment, or a combination of a lump sum and annuity payments. In addition to our pension plans, we currently provide subsidized retiree medical and life insurance benefits (other postretirement benefits) to certain eligible participants. Generally, employees hired after December 31, 1991, are not eligible for the subsidized retiree medical benefits, except for participants that were employees or retirees of Transco Energy Company on December 31, 1995, and other miscellaneous defined participant groups. Subsidized retiree medical benefits for eligible participants age 65 and older are paid through contributions to health reimbursement accounts. Subsidized retiree medical benefits for eligible participants under age 65 are provided through a self-insured medical plan sponsored by us. The self-insured retiree medical plan provides for retiree contributions and contains other cost-sharing features such as deductibles, co-payments, and co-insurance. The accounting for these plans anticipates estimated future increases to our contribution levels to the health reimbursement accounts for participants age 65 and older, as well as future cost-sharing that is consistent with our expressed intent to increase the retiree contribution level generally in line with health care cost increases for participants under age 65. Funded Status The following table presents the changes in benefit obligations and plan assets for pension benefits and other postretirement benefits for the years indicated. Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 (Millions) Change in benefit obligation: Benefit obligation at beginning of year $ 1,544 $ 1,384 $ 233 $ 213 Service cost 59 40 2 2 Interest cost 58 62 9 10 Plan participants’ contributions — — 2 2 Benefits paid (101 ) (86 ) (13 ) (14 ) Plan amendment — — — 1 Actuarial loss (gain) (91 ) 144 (31 ) 21 Settlements (5 ) (3 ) — (1 ) Curtailments — — — (1 ) Other — 3 — — Benefit obligation at end of year 1,464 1,544 202 233 Change in plan assets: Fair value of plan assets at beginning of year 1,293 1,241 208 201 Actual return on plan assets (11 ) 78 (1 ) 13 Employer contributions 65 63 5 6 Plan participants’ contributions — — 2 2 Benefits paid (101 ) (86 ) (13 ) (14 ) Settlements (5 ) (3 ) — — Fair value of plan assets at end of year 1,241 1,293 201 208 Funded status — underfunded $ (223 ) $ (251 ) $ (1 ) $ (25 ) Accumulated benefit obligation $ 1,432 $ 1,516 The underfunded status of our pension plans and other postretirement benefit plans presented in the previous table are recognized in the Consolidated Balance Sheet within the following accounts: December 31, 2015 2014 (Millions) Underfunded pension plans: Current liabilities $ (2 ) $ (2 ) Noncurrent liabilities (221 ) (249 ) Underfunded other postretirement benefit plans: Current liabilities (7 ) (7 ) Noncurrent assets (liabilities) 6 (18 ) The plan assets within our other postretirement benefit plans are intended to be used for the payment of benefits for certain groups of participants. The Current liabilities for the other postretirement benefit plans represent the current portion of benefits expected to be payable in the subsequent year for the groups of participants whose benefits are not expected to be paid from plan assets. The pension plans’ benefit obligation Actuarial loss (gain) of $ (91) million in 2015 is primarily due to the impact of a decrease in the assumed future interest crediting rate for the cash balance pension formula and an increase in the discount rates utilized to calculate the benefit obligation. The pension plans’ benefit obligation Actuarial loss (gain) of $144 million in 2014 is primarily due to the impact of updated mortality tables reflecting increased estimated life expectancies and a decrease in the discount rates utilized to calculate the benefit obligation. The 2015 benefit obligation Actuarial loss (gain) of $ (31) million for our other postretirement benefit plans is primarily due to an increase in the discount rate used to calculate the benefit obligation, tax law changes, and other assumption changes. The 2014 benefit obligation Actuarial loss (gain) of $21 million for our other postretirement benefit plans is primarily due to the impact of the updated mortality tables and a decrease in the discount rates utilized to calculate the benefit obligation. At December 31, 2015 and 2014 , all of our pension plans had a projected benefit obligation and accumulated benefit obligation in excess of plan assets. Pre-tax amounts not yet recognized in Net periodic benefit cost at December 31 are as follows: Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 (Millions) Amounts included in Accumulated other comprehensive income (loss) : Prior service credit $ — $ — $ 11 $ 17 Net actuarial loss (544 ) (593 ) (18 ) (28 ) Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline: Prior service credit N/A N/A $ 19 $ 30 Net actuarial gain (loss) N/A N/A 6 (4 ) In addition to the regulatory liabilities included in the previous table, differences in the amount of actuarially determined Net periodic benefit cost for our other postretirement benefit plans and the other postretirement benefit costs recovered in rates for Transco and Northwest Pipeline are deferred as a regulatory asset or liability. We have regulatory liabilities of $78 million at December 31, 2015 and $62 million at December 31, 2014 , related to these deferrals. These amounts will be reflected in future rates based on the rate structures of these gas pipelines. Net Periodic Benefit Cost Net periodic benefit cost for the years ended December 31 consist of the following: Pension Benefits Other Postretirement Benefits 2015 2014 2013 2015 2014 2013 (Millions) Components of net periodic benefit cost: Service cost $ 59 $ 40 $ 44 $ 2 $ 2 $ 2 Interest cost 58 62 51 9 10 11 Expected return on plan assets (75 ) (76 ) (61 ) (12 ) (12 ) (9 ) Amortization of prior service cost (credit) — — 1 (17 ) (20 ) (12 ) Amortization of net actuarial loss 42 39 60 2 — 4 Net actuarial (gain) loss from settlements and curtailments 2 1 — — (1 ) — Reclassification to regulatory liability — — — 3 4 2 Net periodic benefit cost $ 86 $ 66 $ 95 $ (13 ) $ (17 ) $ (2 ) Items Recognized in Other Comprehensive Income (Loss) and Regulatory Assets/Liabilities Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss) before taxes for the years ended December 31 consist of the following: Pension Benefits Other Postretirement Benefits 2015 2014 2013 2015 2014 2013 (Millions) Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss) : Net actuarial gain (loss) $ 5 $ (142 ) $ 277 $ 8 $ (18 ) $ 23 Prior service (cost) credit — — — — (1 ) 23 Amortization of prior service cost (credit) — — 1 (6 ) (8 ) (4 ) Amortization of net actuarial loss 42 39 60 2 — 1 Loss from settlements and curtailments 2 1 — — 1 — Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss) $ 49 $ (102 ) $ 338 $ 4 $ (26 ) $ 43 Other changes in plan assets and benefit obligations for our other postretirement benefit plans associated with Transco and Northwest Pipeline are recognized in regulatory assets/liabilities. Amounts recognized in regulatory assets/ liabilities for the years ended December 31 consist of the following: 2015 2014 2013 (Millions) Other changes in plan assets and benefit obligations recognized in regulatory (assets) liabilities: Net actuarial gain (loss) $ 10 $ (2 ) $ 62 Prior service credit — — 36 Amortization of prior service credit (11 ) (12 ) (8 ) Amortization of net actuarial loss — — 3 Pre-tax amounts expected to be amortized in Net periodic benefit cost in 2016 are as follows: Pension Benefits Other Postretirement Benefits (Millions) Amounts included in Accumulated other comprehensive income (loss) : Prior service credit $ — $ (6 ) Net actuarial loss 31 — Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline: Prior service credit N/A $ (9 ) Net actuarial loss N/A — Key Assumptions The weighted-average assumptions utilized to determine benefit obligations as of December 31 are as follows: Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 Discount rate 4.38 % 3.96 % 4.50 % 4.12 % Rate of compensation increase 4.88 4.62 N/A N/A The weighted-average assumptions utilized to determine Net periodic benefit cost for the years ended December 31 are as follows: Pension Benefits Other Postretirement Benefits 2015 2014 2013 2015 2014 2013 Discount rate 3.96 % 4.68 % 3.43 % 4.12 % 4.80 % 3.97 % Expected long-term rate of return on plan assets 6.38 6.85 5.90 5.70 6.11 5.26 Rate of compensation increase 4.62 4.56 4.57 N/A N/A N/A Effective December 31, 2014, the mortality assumptions used to determine the benefit obligations for our pension and other postretirement benefit plans were updated to reflect generational projection mortality tables. These mortality tables generally reflect increased estimated life expectancy. The assumed health care cost trend rate for 2016 is 7.9 percent. This rate decreases to 4.5 percent by 2025 . A one-percentage-point change in assumed health care cost trend rates would have the following effects: Point increase Point decrease (Millions) Effect on total of service and interest cost components $ — $ — Effect on other postretirement benefit obligation 7 (6 ) Plan Assets Plan assets for our pension and other postretirement benefit plans consist primarily of equity and fixed income securities including commingled investment funds invested in equity and fixed income securities. The plans’ investment policy provides for a strategy in accordance with the Employee Retirement Income Security Act (ERISA), which governs the investment of the assets in a diversified portfolio. The plans follow a policy of diversifying the investments across various asset classes and investment managers. Additionally, the investment returns on approximately 38 percent of the other postretirement benefit plan assets are subject to income tax; therefore, certain investments are managed in a tax efficient manner. The investment policy for the pension plans includes a general target asset allocation at December 31, 2015 of 60 percent equity securities and 40 percent fixed income securities. The target allocation includes the investments in equity and fixed income commingled investment funds. The investment policy allows for a broad range of asset allocations that permit the plans to de-risk in response to changes in the plans’ funded status. Equity securities may include U.S. equities and non-U.S. equities. Investment in Williams’ securities or an entity in which Williams has a majority ownership is prohibited in the pension plans except where these securities may be owned in a commingled investment fund in which the plans’ trusts invest. No more than 5 percent of the total stock portfolio valued at market may be invested in the common stock of any one corporation. Fixed income securities may consist of U.S. as well as international instruments, including emerging markets. The fixed income strategies may invest in government, corporate, asset-backed securities, and mortgage-backed obligations. The weighted-average credit rating of the fixed income strategies must be at least “investment grade” including ratings by Moody’s and/or Standard & Poor’s. No more than 5 percent of the total fixed income portfolio may be invested in the fixed income securities of any one issuer with the exception of bond index funds and U.S. government guaranteed and agency securities. The following securities and transactions are not authorized: unregistered securities, commodities or commodity contracts, short sales or margin transactions, or other leveraging strategies. Investment strategies using direct investments in derivative securities require approval and, historically, have not been used; however, these instruments may be used in commingled investment funds. Additionally, real estate equity, natural resource property, venture capital, leveraged buyouts, and other high-return, high-risk investments are generally restricted. As of December 31, 2015 , 12 active investment managers and one passive investment manager managed substantially all of the pension plans’ funds and the other postretirement benefit plans’ funds were substantially managed by four active investment managers and one passive investment manager. Each of the managers had responsibility for managing a specific portion of these assets and each investment manager was responsible for 1 percent to 28 percent of the assets. There are no significant concentrations of risk within the plans’ investment securities because of the diversity of the types of investments, diversity of the various industries, and the diversity of the fund managers and investment strategies. Generally, the investments held in the plans are publicly traded, therefore, minimizing liquidity risk in the portfolio. The fair values of our pension plan assets at December 31, 2015 and 2014 by asset class are as follows: 2015 Quoted Prices Significant Significant Total (Millions) Pension assets: Cash management fund $ 8 $ — $ — $ 8 Equity securities: U.S. large cap 83 — — 83 U.S. small cap 64 — — 64 Fixed income securities (1): U.S. Treasury securities 65 — — 65 Government and municipal bonds — 8 — 8 Mortgage and asset-backed securities — 87 — 87 Corporate bonds — 145 — 145 Insurance company investment contracts and other — 5 — 5 $ 220 $ 245 $ — 465 Commingled investment funds measured at net asset value practical expedient (3): Equities — U.S. large cap 367 Equities — International small cap 27 Equities — International emerging markets 50 Equities — International developed markets 153 Fixed income — U.S. long duration 95 Fixed income — Corporate bonds 84 Total assets at fair value at December 31, 2015 $ 1,241 2014 Quoted Prices Significant Significant Total (Millions) Pension assets: Cash management fund $ 25 $ — $ — $ 25 Equity securities: U.S. large cap 221 — — 221 U.S. small cap 139 — — 139 International developed markets large cap growth — 60 — 60 Fixed income securities (1): U.S. Treasury securities 31 — — 31 Mortgage-backed securities — 65 — 65 Corporate bonds — 222 — 222 Insurance company investment contracts and other — 7 — 7 $ 416 $ 354 $ — 770 Commingled investment funds measured at net asset value practical expedient (3): Equities — U.S. large cap 189 Equities — International small cap 24 Equities — Emerging markets value 27 Equities — Emerging markets growth 19 Equities — International developed markets large cap value 101 Fixed income — Corporate bonds 163 Total assets at fair value at December 31, 2014 $ 1,293 The fair values of our other postretirement benefits plan assets at December 31, 2015 and 2014 by asset class are as follows: 2015 Quoted Prices Significant Significant Total (Millions) Other postretirement benefit assets: Cash management funds $ 11 $ — $ — $ 11 Equity securities: U.S. large cap 37 — — 37 U.S. small cap 20 — — 20 International developed markets large cap growth 1 9 — 10 Emerging markets growth — 1 — 1 Fixed income securities (2): U.S. Treasury securities 7 — — 7 Government and municipal bonds — 12 — 12 Mortgage and asset-backed securities — 9 — 9 Corporate bonds — 15 — 15 $ 76 $ 46 $ — 122 Commingled investment funds measured at net asset value practical expedient (3): Equities — U.S. large cap 37 Equities — International small cap 3 Equities — International emerging markets 5 Equities — International developed markets 16 Fixed income — U.S. long duration 10 Fixed income — Corporate bonds 8 Total assets at fair value at December 31, 2015 $ 201 2014 Quoted Prices Significant Significant Total (Millions) Other postretirement benefit assets: Cash management funds $ 13 $ — $ — $ 13 Equity securities: U.S. large cap 53 — — 53 U.S. small cap 28 — — 28 International developed markets large cap growth — 15 — 15 Emerging markets growth 1 2 — 3 Fixed income securities (2): U.S. Treasury securities 3 — — 3 Government and municipal bonds — 11 — 11 Mortgage-backed securities — 7 — 7 Corporate bonds — 23 — 23 $ 98 $ 58 $ — 156 Commingled investment funds measured at net asset value practical expedient (3): Equities — U.S. large cap 19 Equities — International small cap 2 Equities — Emerging markets value 3 Equities — Emerging markets growth 2 Equities — International developed markets large cap value 10 Fixed income — Corporate bonds 16 Total assets at fair value at December 31, 2014 $ 208 ____________ (1) The weighted-average credit quality rating of the pension assets fixed income security portfolio is investment grade with a weighted-average duration of approximately 8 years for 2015 and 6 years for 2014 . (2) The weighted-average credit quality rating of the other postretirement benefit assets fixed income security portfolio is investment grade with a weighted-average duration of approximately 7 years for 2015 and 5 years for 2014 . (3) In accordance with our adoption of ASU 2015-07, investments measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified within the fair value hierarchy. (See Note 1 – General, Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies .) The stated intents of the funds vary based on each commingled fund’s investment objective. These objectives generally include strategies to replicate or outperform various market indices. Certain standard withdrawal restrictions generally apply, which may include redemption notification period restrictions ranging from 10 to 30 days. Additionally, the fund managers retain the right to restrict withdrawals from and/or purchases into the funds so as not to disadvantage other investors in the funds. Generally, the funds also reserve the right to make all or a portion of the redemption in-kind rather than in cash or a combination of cash and in-kind. The fair value measurement level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement of an asset. Shares of the cash management funds are valued at fair value based on published market prices as of the close of business on the last business day of the year, which represents the net asset values of the shares held. The fair values of equity securities traded on U.S. exchanges are derived from quoted market prices as of the close of business on the last business day of the year. The fair values of equity securities traded on foreign exchanges are also derived from quoted market prices as of the close of business on an active foreign exchange on the last business day of the year. However, the valuation requires translation of the foreign currency to U.S. dollars and this translation is considered an observable input to the valuation. The fair values of all commingled investment funds are determined based on the net asset values per unit of each of the funds. The net asset values per unit represent the aggregate value of the fund’s assets at fair value less liabilities, divided by the number of units outstanding. The fair values of fixed income securities, except U.S. Treasury securities, are determined using pricing models. These pricing models incorporate observable inputs such as benchmark yields, reported trades, broker/dealer quotes, and issuer spreads for similar securities to determine fair value. The U.S. Treasury securities are valued at fair value based on closing prices on the last business day of the year reported in the active market in which the security is traded. The investment contracts with insurance companies are valued at fair value by discounting the cash flow of a bond using a yield to maturity based on an investment grade index or comparable index with a similar maturity value, maturity period, and nominal coupon rate. There have been no significant changes in the preceding valuation methodologies used at December 31, 2015 and 2014 . Additionally, there were no transfers or reclassifications of investments between Level 1 and Level 2 from December 2014 to December 2015 . If transfers between levels had occurred, the transfers would have been recognized as of the end of the period. Plan Benefit Payments and Employer Contributions Following are the expected benefits to be paid by the plans. These estimates are based on the same assumptions previously discussed and reflect future service as appropriate. The actuarial assumptions are based on long-term expectations and include, but are not limited to, assumptions as to average expected retirement age and form of benefit payment. Actual benefit payments could differ significantly from expected benefit payments if near-term participant behaviors differ significantly from the actuarial assumptions. Pension Benefits Other Postretirement Benefits (Millions) 2016 $ 95 $ 13 2017 102 13 2018 105 13 2019 106 13 2020 110 14 2021-2025 578 66 In 2016 , we expect to contribute approximately $60 million to our tax-qualified pension plans and approximately $2 million to our nonqualified pension plans, for a total of approximately $62 million , and approximately $7 million to our other postretirement benefit plans. Defined Contribution Plans We also maintain defined contribution plans for the benefit of substantially all of our employees. Generally, plan participants may contribute a portion of their compensation on a pre-tax and after-tax basis in accordance with the plans’ guidelines. We match employees’ contributions up to certain limits. Our matching contributions charged to expense were $39 million in 2015 , $39 million in 2014 , and $27 million in 2013 . The increase in expense beginning in 2014 is primarily due to the impact of the consolidation of ACMP beginning in the third quarter of 2014. (See Note 2 – Acquisitions .)

Inventories

Inventories	12 Months Ended
	Dec. 31, 2015
Inventory, Net [Abstract]
Inventories [Text Block]	Note 10 – Inventories December 31, 2015 2014 (Millions) Natural gas liquids, olefins, and natural gas in underground storage $ 57 $ 150 Materials, supplies, and other 70 81 $ 127 $ 231

Property, Plant, and Equipment

Property, Plant, and Equipment	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment [Text Block]	Note 11 – Property, Plant, and Equipment The following table presents nonregulated and regulated Property, plant, and equipment – net as presented on the Consolidated Balance Sheet for the years ended: Estimated Useful Life (1) (Years) Depreciation Rates (1) (%) December 31, 2015 2014 (Millions) Nonregulated: Natural gas gathering and processing facilities 5 - 40 $ 20,789 $ 18,749 Construction in progress Not applicable 1,366 2,648 Other 2 - 45 2,170 1,850 Regulated: Natural gas transmission facilities 1.20 - 6.97 12,189 10,867 Construction in progress Not applicable Not applicable 941 985 Other 5 - 45 1.35 - 33.33 1,584 1,336 Total property, plant, and equipment, at cost 39,039 36,435 Accumulated depreciation and amortization (9,460 ) (8,354 ) Property, plant, and equipment — net $ 29,579 $ 28,081 __________ (1) Estimated useful life and depreciation rates are presented as of December 31, 2015 . Depreciation rates and estimated useful lives for regulated assets are prescribed by the FERC. Depreciation and amortization expense for Property, plant, and equipment – net was $1,382 million , $967 million , and $752 million in 2015 , 2014 , and 2013 , respectively. Regulated Property, plant, and equipment – net includes approximately $706 million and $746 million at December 31, 2015 and 2014 , respectively, related to amounts in excess of the original cost of the regulated facilities within our gas pipeline businesses as a result of our prior acquisitions. This amount is being amortized over 40 years using the straight-line amortization method. Current FERC policy does not permit recovery through rates for amounts in excess of original cost of construction. Asset Retirement Obligations Our accrued obligations relate to underground storage caverns, offshore platforms and pipelines, fractionation and compression facilities, gas gathering well connections and pipelines, and gas transmission facilities. At the end of the useful life of each respective asset, we are legally obligated to plug storage caverns and remove any related surface equipment, to restore land and remove surface equipment at gas processing, fractionation, and compression facilities, to dismantle offshore platforms and appropriately abandon offshore pipelines, to cap certain gathering pipelines at the wellhead connection and remove any related surface equipment, and to remove certain components of gas transmission facilities from the ground. The following table presents the significant changes to our ARO, of which $858 million and $791 million are included in Other noncurrent liabilities with the remaining current portion in Accrued liabilities at December 31, 2015 and 2014 , respectively. December 31, 2015 2014 (Millions) Beginning balance $ 831 $ 561 Liabilities incurred 42 101 Liabilities settled (1) (3 ) (21 ) Accretion expense 60 44 Revisions (2) (15 ) 146 Ending balance $ 915 $ 831 ___________ (1) For 2014, liabilities settled include $7 million related to the abandonment of certain of Transco’s natural gas storage caverns that are associated with a leak in 2010. (2) Several factors are considered in the annual review process, including inflation rates, current estimates for removal cost, discount rates, and the estimated remaining useful life of the assets. The 2015 revisions reflect changes in removal cost estimates and the estimated remaining useful life of assets, a decrease in the inflation rate, and increases in the discount rates used in the annual review process. The 2014 revisions primarily reflect an increase in the estimated retirement costs for our offshore pipelines, an increase in the inflation rate, and decreases in the discount rates used in the annual review process. The funds Transco collects through a portion of its rates to fund its ARO are deposited into an external trust account dedicated to funding its ARO (ARO Trust). (See Note 17 – Fair Value Measurements, Guarantees, and Concentration of Credit Risk .) Under its current rate settlement, Transco’s annual funding obligation is approximately $36 million , with installments to be deposited monthly.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Intangible Assets Disclosure [Text Block]	Note 12 – Goodwill and Other Intangible Assets Goodwill Changes in the carrying amount of goodwill by reportable segment for the periods indicated are as follows: Williams Partners (Millions) December 31, 2014 $ 1,120 Purchase accounting adjustment 25 Impairment (1,098 ) December 31, 2015 $ 47 Our goodwill is not subject to amortization, but is evaluated at least annually for impairment or more frequently if impairment indicators are present. We did not identify or recognize any impairments to goodwill in connection with our annual evaluation of goodwill for impairment (performed as of October 1) during the years ended December 31, 2014 and 2013 . During 2015, we performed an interim assessment of certain goodwill within the Williams Partners segment as of September 30, 2015, but the estimated fair value of the reporting unit evaluated exceeded its carrying amount and thus no impairment charge was recognized. We performed an additional goodwill impairment evaluation as of December 31, 2015 , of the goodwill recorded within the Williams Partners segment. As a result of this evaluation, we recorded goodwill impairment charges totaling $1.098 billion . (See Note 17 – Fair Value Measurements, Guarantees, and Concentration of Credit Risk .) Other Intangible Assets The gross carrying amount and accumulated amortization of Other intangible assets – net of accumulated amortization at December 31 are as follows: 2015 2014 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization (Millions) Contractual customer relationships $ 10,633 $ (663 ) $ 10,763 $ (310 ) Other intangible assets – net of accumulated amortization primarily relate to gas gathering, processing, and fractionation contractual customer relationships recognized in the ACMP and Eagle Ford acquisitions (See Note 2 – Acquisitions ) as well as the 2012 acquisitions from Delphi Midstream Partners, LLC (Laser) and Caiman Energy, LLC (Caiman). The decrease in the gross carrying amount of Other intangible assets – net of accumulated amortization during 2015 is primarily related to the $168 million decrease from the purchase price allocation adjustment recorded for the ACMP acquisition in the first quarter of 2015, partially offset by the $32 million increase due to the Eagle Ford acquisition in the second quarter of 2015 (see Note 2 – Acquisitions ). The intangible assets are being amortized on a straight-line basis over an initial period of 30 years which represents a portion of the term over which the contractual customer relationships are expected to contribute to our cash flows. We expense costs incurred to renew or extend the terms of our gas gathering, processing, and fractionation contracts with customers. Based on the estimated future revenues during the contract periods (as estimated at the time of the respective acquisition), the weighted-average periods prior to the next renewal or extension of the contractual customer relationships associated with the ACMP, Eagle Ford, Laser, and Caiman acquisitions were approximately 17 years , 10 years , 9 years , and 18 years , respectively. Although a significant portion of the expected future cash flows associated with these contractual customer relationships are dependent on our ability to renew or extend the arrangements beyond the initial contract periods, these expected future cash flows are significantly influenced by the scope and pace of our producer customers’ drilling programs. Once producer customers’ wells are connected to our gathering infrastructure, their likelihood of switching to another provider before the wells are abandoned is reduced due to the significant capital investment required. The amortization expense related to Other intangible assets – net of accumulated amortization was $353 million , $209 million , and $60 million in 2015 , 2014 , and 2013 , respectively. The estimated amortization expense for each of the next five succeeding fiscal years is approximately $354 million.

Accrued Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2015
Accrued Liabilities, Current [Abstract]
Accrued Liabilities [Text Block]	Note 13 – Accrued Liabilities December 31, 2015 2014 (Millions) Interest on debt $ 284 $ 268 Employee costs 215 167 Special distribution repayable to Gulfstream (See Note 5 - Investing Activities) 149 — Deferred income 94 82 Asset retirement obligations 57 40 Other, including other loss contingencies 279 343 $ 1,078 $ 900

Debt, Banking Arrangements, and

Debt, Banking Arrangements, and Leases	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	Note 14 – Debt, Banking Arrangements, and Leases Long-Term Debt December 31, 2015 2014 (Millions) Unsecured: Transco: 6.4% Notes due 2016 (2) $ 200 $ 200 6.05% Notes due 2018 250 250 7.08% Debentures due 2026 8 8 7.25% Debentures due 2026 200 200 5.4% Notes due 2041 375 375 4.45% Notes due 2042 400 400 Northwest Pipeline: 7% Notes due 2016 175 175 5.95% Notes due 2017 185 185 6.05% Notes due 2018 250 250 7.125% Debentures due 2025 85 85 WPZ: 3.8% Notes due 2015 (1) — 750 7.25% Notes due 2017 600 600 5.25% Notes due 2020 1,500 1,500 4.125% Notes due 2020 600 600 4% Notes due 2021 500 500 5.875% Notes due 2021 — 750 3.6% Notes due 2022 1,250 — 3.35% Notes due 2022 750 750 6.125% Notes due 2022 750 750 4.5% Notes due 2023 600 600 4.875% Notes due 2023 1,400 1,400 4.3% Notes due 2024 1,000 1,000 4.875% Notes due 2024 750 750 3.9% Notes due 2025 750 750 4.0% Notes due 2025 750 — December 31, 2015 2014 (Millions) 6.3% Notes due 2040 $ 1,250 $ 1,250 5.8% Notes due 2043 400 400 5.4% Notes due 2044 500 500 4.9% Notes due 2045 500 500 5.1% Notes due 2045 1,000 — Term Loan, variable interest rate, due 2018 850 — Credit facility loans 1,310 640 WMB: 7.875% Notes due 2021 371 371 3.7% Notes due 2023 850 850 4.55% Notes due 2024 1,250 1,250 7.5% Debentures due 2031 339 339 7.75% Notes due 2031 252 252 8.75% Notes due 2032 445 445 5.75% Notes due 2044 650 650 Various — 5.5% to 10.25% Notes and Debentures due 2019 to 2033 55 55 Credit facility loans 650 370 Capital lease obligations 1 5 Debt issuance costs (123 ) (108 ) Net unamortized debt premium (discount) 110 187 Total long-term debt, including current portion 23,988 20,784 Long-term debt due within one year (176 ) (4 ) Long-term debt $ 23,812 $ 20,780 ___________ (1) Presented as long-term debt at December 31, 2014, due to WPZ's intent and ability to refinance. (2) Presented as long-term debt at December 31, 2015, due to Transco’s intent and ability to refinance. Certain of our debt agreements contain covenants that restrict or limit, among other things, our ability to create liens supporting indebtedness, sell assets, and incur additional debt. Default of these agreements could also restrict our ability to make certain distributions or repurchase equity. The following table presents aggregate minimum maturities of long-term debt, excluding net unamortized debt premium (discount), debt issuance costs, and capital lease obligations, for each of the next five years: December 31, 2015 (Millions) 2016 $ 175 2017 785 2018 1,350 2019 32 2020 2,121 Provisions concerning ACMP long-term debt Certain long-term debt originally issued by ACMP totaling $2.9 billion has provisions that would require WPZ to make an offer to repurchase such notes at 101 percent of the principle amount should WPZ’s credit be downgraded by either Moody’s Investor Service or Standard and Poor’s within a period of ninety days following the completion of the proposed ETC Merger. Issuances and retirements On January 22, 2016, Transco issued $1 billion of 7.85 percent senior unsecured notes due 2026 to investors in a private debt placement. Transco intends to use the net proceeds from the offering to repay debt and to fund capital expenditures. In December 2015, WPZ borrowed $850 million on a variable interest rate loan with certain lenders due 2018. At December 31, 2015 the interest rate was 1.85 percent . WPZ used the proceeds for working capital, capital expenditures, and for general partnership purposes. On April 15, 2015, WPZ paid $783 million , including a redemption premium, to early retire $750 million of 5.875 percent senior notes due 2021 with a carrying value of $797 million . On March 3, 2015, WPZ completed a public offering of $1.25 billion of 3.6 percent senior unsecured notes due 2022, $750 million of 4 percent senior unsecured notes due 2025, and $1 billion of 5.1 percent senior unsecured notes due 2045. WPZ used the net proceeds to repay amounts outstanding under its commercial paper program and credit facility, to fund capital expenditures, and for general partnership purposes. WPZ retired $750 million of 3.8 percent senior unsecured notes that matured on February 15, 2015. On June 27, 2014, Pre-merger WPZ completed a public offering of $750 million of 3.9 percent senior unsecured notes due 2025 and $500 million of 4.9 percent senior unsecured notes due 2045. Pre-merger WPZ used the net proceeds to repay amounts outstanding under its commercial paper program, to fund capital expenditures, and for general partnership purposes. On June 24, 2014, we completed a public offering of $1.25 billion of 4.55 percent senior unsecured notes due 2024 and $650 million of 5.75 percent unsecured notes due 2044. We used the net proceeds to finance a portion of the ACMP Acquisition. (See Note 2 – Acquisitions .) On March 4, 2014, Pre-merger WPZ completed a public offering of $1 billion of 4.3 percent senior unsecured notes due 2024 and $500 million of 5.4 percent senior unsecured notes due 2044. Pre-merger WPZ used the net proceeds to repay amounts outstanding under its commercial paper program, to fund capital expenditures, and for general partnership purposes. Credit Facilities December 31, 2015 Available Outstanding (Millions) WMB Long-term credit facility $ 1,500 $ 650 Letters of credit under certain bilateral bank agreements 14 WPZ Long-term credit facility (1) 3,500 1,310 Letters of credit under certain bilateral bank agreements 2 Short-term credit facility 150 — ________________ (1) In managing our available liquidity, we do not expect a maximum outstanding amount in excess of the capacity of our credit facility inclusive of any outstanding amounts under our commercial paper program. WMB long-term credit facility On February 2, 2015, we entered into the Second Amended and Restated Credit Agreement. The aggregate commitments available remained at $1.5 billion , with up to an additional $500 million increase in aggregate commitments available under certain circumstances. The maturity date of the credit facility was extended to February 2, 2020. However, we may request up to two extensions of the maturity date each for an additional one year period to allow a maturity date as late as February 2, 2022, under certain circumstances. The agreement also allows for swing line loans up to an aggregate amount of $50 million , subject to available capacity under the credit facility, and the letters of credit up to $675 million . The agreements governing the credit facilities contain the following terms and conditions: • Various covenants may limit, among other things, a borrower’s and its material subsidiaries’ ability to grant certain liens supporting indebtedness, merge or consolidate, sell all or substantially all of its assets, enter into certain affiliate transactions, make certain distributions during an event of default, make investments, and allow any material change in the nature of its business. • If an event of default with respect to a borrower occurs under its respective credit facility, the lenders will be able to terminate the commitments for the respective borrowers and accelerate the maturity of any loans of the defaulting borrower under the respective credit facility agreement and exercise other rights and remedies. • Each time funds are borrowed under our credit facility, the borrower may choose from two methods of calculating interest: a fluctuating base rate equal to the bank’s alternate base rate plus an applicable margin or a periodic fixed rate equal to LIBOR plus an applicable margin. The borrower is required to pay a commitment fee based on the unused portion of its respective credit facility. The applicable margin and the commitment fee are determined for us by reference to a pricing schedule based on our senior unsecured long-term debt ratings. Significant financial covenants under the agreement require the ratio of debt to EBITDA (each as defined in the credit agreement) be no greater than 5 to 1, except for the fiscal quarter and the two following fiscal quarters in which one or more acquisitions has been executed, in which case the ratio of debt to EBITDA is to be no greater than 5.5 to 1. We are in compliance with these financial covenants as measured at December 31, 2015. As of February 25, 2016, $475 million is outstanding under our long-term credit facility. WPZ long-term credit facilities Prior to their merger both WPZ and ACMP had separate credit facilities that terminated on February 2, 2015. On February 2, 2015, WPZ along with Transco, Northwest Pipeline, the lenders named therein, and an administrative agent entered into the Second Amended & Restated Credit Agreement with aggregate commitments available of $3.5 billion , with up to an additional $500 million increase in aggregate commitments available under certain circumstances. The maturity date of the credit facility is February 2, 2020. However, the co-borrowers may request up to two extensions of the maturity date each for an additional one year period to allow a maturity date as late as February 2, 2022, under certain circumstances. The agreement allows for swing line loans up to an aggregate amount of $150 million , subject to available capacity under the credit facility, and letters of credit commitments of $1.125 billion . Transco and Northwest Pipeline are each able to borrow up to $500 million under this credit facility to the extent not otherwise utilized by the other co-borrowers. On December 18, 2015, WPZ along with Transco, Northwest Pipeline, the lenders named therein and an administrative agent entered into the Amendment No. 1 to Second Amended & Restated Credit Agreement modifying the thresholds specified in the covenant related to the maximum ratio of WPZ’s debt to EBITDA. The agreement governing this credit facility contains the following terms and conditions: • Various covenants may limit, among other things, a borrower’s and its material subsidiaries’ ability to grant certain liens supporting indebtedness, merge or consolidate, sell all or substantially all of its assets, enter into certain affiliate transactions, make certain distributions during an event of default, enter into certain restrictive agreements, and allow any material change in the nature of its business. • If an event of default with respect to a borrower occurs under the credit facility, the lenders will be able to terminate the commitments for all borrowers and accelerate the maturity of any loans of the defaulting borrower under the credit facility agreement and exercise other rights and remedies. • Other than swing line loans, each time funds are borrowed, the borrower must choose whether such borrowing will be an alternate base rate borrowing or a Eurodollar borrowing. If such borrowing is an alternate base rate borrowing, interest is calculated on the basis of the greater of (a) the Prime Rate, (b) the Federal Funds Effective Rate plus one half of 1 percent and (c) a periodic fixed rate equal to the London Interbank Offered Rate (LIBOR) plus 1 percent , plus, in the case of each of (a), (b) and (c), an applicable margin. If the borrowing is a Eurodollar borrowing, interest is calculated on the basis of LIBOR for the relevant period plus an applicable margin. Interest on swingline loans is calculated as the sum of the alternate base rate plus an applicable margin. The borrower is required to pay a commitment fee based on the unused portion of the credit facility. The applicable margin and the commitment fee are determined for each borrower by reference to a pricing schedule based on such borrower’s senior unsecured long-term debt ratings. Significant financial covenants under the agreement require the ratio of debt to EBITDA, each as defined in the credit facility, be no greater than: • 5.75 to 1, for the quarters ending December 31, 2015, March 31, 2016 and June 30, 2016; • 5.50 to 1, for the quarters ending September 30, 2016 and December 31, 2016; • 5.00 to 1, for the quarter ending March 31, 2017 and each subsequent fiscal quarter, except for the the fiscal quarter and the two following fiscal quarters in which one or more acquisitions has been executed, in which case the ratio of debt to EBITDA is to be no greater than 5.5 to 1.00. The ratio of debt to capitalization (defined as net worth plus debt) must be no greater than 65 percent for each Transco and Northwest Pipeline. WPZ is in compliance with these financial covenants as measured at December 31, 2015. As of February 25, 2016, $925 million is outstanding under the long-term credit facility. WPZ short-term credit facilities On February 3, 2015, WPZ entered into a short-term $1.5 billion credit facility and terminated it on March 3, 2015. On August 26, 2015, WPZ entered into a credit agreement providing for a $1.0 billion short-term credit facility with a maturity date of August 24, 2016. On December 23, 2015, WPZ’s short-term credit facility capacity decreased to $150 million in conjunction with entering into the $850 million term loan. The agreement governing this credit facility contains the following terms and conditions: • This facility becomes available when the aggregate amount of outstanding loans under our long-term credit facility plus outstanding commercial paper borrowings reach a total of $3.5 billion . • Various covenants that limit, among other things, a borrower’s and its respective material subsidiaries’ ability to grant certain liens supporting indebtedness, merge or consolidate, sell all or substantially all of its assets in certain circumstances, enter into certain affiliate transactions, make certain distributions during an event of default, enter into certain restrictive agreements and allow any material change in the nature of its business. • If an event of default with respect to a borrower occurs under the credit facility, the lenders will be able to terminate the commitments and accelerate the maturity of the loans and exercise other rights and remedies. • Each time funds are borrowed under the credit facility, the borrower may choose from two methods of calculating interest: a fluctuating base rate equal to an alternate base rate plus an applicable margin, or a periodic fixed rate equal to LIBOR plus an applicable margin. The borrower is required to pay a commitment fee based on the unused portion of the credit facility. The applicable margin and the commitment fee are determined by reference to a pricing schedule based on the borrower’s senior unsecured long-term debt ratings. The significant financial covenant requires the ratio of debt to EBITDA, each as defined in the credit agreement, as of the last day of any fiscal quarter for which financial statements have been delivered to be no greater than 6.0 to 1.0. WPZ is in compliance with these financial covenants as measured at December 31, 2015. Commercial Paper Program On February 2, 2015, WPZ amended and restated the commercial paper program for the ACMP Merger and to allow a maximum outstanding amount of unsecured commercial paper notes of $3 billion . The maturities of the commercial paper notes vary but may not exceed 397 days from the date of issuance. The commercial paper notes are sold under customary terms in the commercial paper market and are issued at a discount from par, or, alternatively, are sold at par and bear varying interest rates on a fixed or floating basis. Proceeds from these notes are used for general partnership purposes, including funding capital expenditures, working capital, and partnership distributions. We classify WPZ’s commercial paper outstanding in Current liabilities in the Consolidated Balance Sheet , as the outstanding notes at December 31, 2015 and December 31, 2014 , have maturity dates less than three months from the date of issuance. At December 31, 2015 , WPZ had $499 million in Commercial paper outstanding at a weighted average interest rate of 0.92 percent and at December 31, 2014 , WPZ had $798 million in Commercial paper outstanding at a weighted average interest rate of 0.92 percent . Cash Payments for Interest (Net of Amounts Capitalized) Cash payments for interest (net of amounts capitalized) were $1.023 billion in 2015, $681 million in 2014, and $472 million in 2013. Restricted Net Assets of Subsidiaries We have considered the guidance in the Securities and Exchange Commission’s Regulation S-X related to restricted net assets of subsidiaries. In accordance with Rule 4-08(e) of Regulation S-X, we have determined that certain net assets of our subsidiaries are considered restricted under this guidance and exceed 25 percent of our consolidated net assets. As of December 31, 2015, substantially all of these restricted net assets relate to the net assets of WPZ, which are technically considered restricted under this accounting rule due to terms within WPZ’s partnership agreement that govern the partnerships’ assets. Our interest in WPZ’s net assets that are considered to be restricted at December 31, 2015 was $14 billion . Leases-Lessee The future minimum annual rentals under noncancelable operating leases, are payable as follows: December 31, 2015 (Millions) 2016 $ 86 2017 74 2018 56 2019 45 2020 39 Thereafter 119 Total $ 419 Total rent expense was $164 million in 2015, $109 million in 2014, and $58 million in 2013 and primarily included in Operating and maintenance expenses and Selling, general, and administrative expenses in the Consolidated Statement of Operations . Accounting Standards Issued and Adopted In April 2015, the FASB issued ASU 2015-03 “Interest - Imputation of Interest: Simplifying the Presentation of Debt Issuance Costs” (ASU 2015-03). ASU 2015-03 simplifies the presentation of debt issuance costs by requiring such costs be presented as a deduction from the corresponding debt liability. Subsequently, in August 2015, the FASB issued ASU 2015-15 “Interest-Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements-Amendments to SEC Paragraphs Pursuant to Staff Announcement at June 18, 2015 EITF Meeting” (ASU 2015-15). In ASU 2015-15 the FASB stated that the guidance in ASU 2015-03 did not address the presentation or subsequent measurement of debt issuance costs related to line-of-credit arrangements, and entities are permitted to defer and present debt issuance costs related to line-of-credit arrangements as assets. The standards are effective for financial statements issued for interim and annual reporting periods beginning after December 15, 2015, and require retrospective presentation. Early adoption is permitted. We elected to early adopt these standards for the periods presented. Accordingly, $123 million and $108 million of debt issuance costs as of December 31, 2015 and 2014, respectively, are now reflected as a direct reduction from Long-term debt in our Consolidated Balance Sheet . Debt issuance costs related to our credit facilities are presented in Regulatory assets, deferred charges, and other in the Consolidated Balance Sheet .

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Stockholders' Equity [Text Block]	Note 15 – Stockholders' Equity Cash dividends declared per common share were $2.45 , $1.9575 , and $1.4375 for 2015 , 2014 , and 2013 , respectively. On June 23, 2014, we issued 61 million shares of common stock in a public offering at a price of $57.00 per share. That amount includes 8 million shares purchased pursuant to the full exercise of the underwriter’s option to purchase additional shares. The net proceeds of $3.378 billion were used in July 2014 to finance a portion of the ACMP Acquisition. (See Note 2 – Acquisitions .) AOCI The following table presents the changes in AOCI by component, net of income taxes: Cash Flow Hedges Foreign Currency Translation Pension and Other Post Retirement Benefits Total (Millions) Balance at December 31, 2014 $ (1 ) $ 31 $ (371 ) $ (341 ) Other comprehensive income (loss) before reclassifications 3 (134 ) 8 (123 ) Amounts reclassified from accumulated other comprehensive income (loss) (3 ) — 25 22 Other comprehensive income (loss) — (134 ) 33 (101 ) Balance at December 31, 2015 $ (1 ) $ (103 ) $ (338 ) $ (442 ) Reclassifications out of AOCI are presented in the following table by component for the year ended December 31, 2015 : Component Reclassifications Classification (Millions) Cash flow hedges: Energy commodity contracts $ (3 ) Product sales Total cash flow hedges, before income taxes (3 ) Pension and other postretirement benefits: Amortization of prior service cost (credit) included in net periodic benefit cost (6 ) Note 9 – Employee Benefit Plans Amortization of actuarial (gain) loss included in net periodic benefit cost 46 Note 9 – Employee Benefit Plans Total pension and other postretirement benefits, before income taxes 40 Reclassifications before income taxes 37 Income tax benefit (15 ) Provision (benefit) for income taxes Reclassifications during the period $ 22

Equity-Based Compensation

Equity-Based Compensation	12 Months Ended
	Dec. 31, 2015
Share-based Compensation [Abstract]
Equity-Based Compensation [Text Block]	Note 16 – Equity-Based Compensation Williams’ Plan Information On May 17, 2007, our stockholders approved The Williams Companies, Inc. 2007 Incentive Plan (the Plan) that provides common-stock-based awards to both employees and nonmanagement directors and reserved 19 million new shares for issuance. On May 20, 2010 and May 22, 2014, our stockholders approved amendments and restatements of the Plan to increase by 11 million and 10 million , respectively, the number of new shares authorized for making awards under the Plan, among other changes. The Plan permits the granting of various types of awards including, but not limited to, restricted stock units and stock options. At December 31, 2015 , 28 million shares of our common stock were reserved for issuance pursuant to existing and future stock awards, of which 19 million shares were available for future grants. Additionally, on May 17, 2007, our stockholders approved an Employee Stock Purchase Plan (ESPP) which authorized up to 2 million new shares of our common stock to be available for sale under the ESPP. On May 22, 2014, our stockholders approved an amendment and restatement of the ESPP to increase by 1.6 million the number of new shares authorized for sale under the ESPP. The ESPP enables eligible participants to purchase our common stock through payroll deductions not exceeding an annual amount of $15,000 per participant. The ESPP provides for offering periods during which shares may be purchased and continues until the earliest of (1) the Board of Directors terminates the ESPP, (2) the sale of all shares available under the ESPP, or (3) the tenth anniversary of the date the ESPP was approved by the stockholders. Offering periods are from January through June and from July through December. Generally, all employees are eligible to participate in the ESPP, with the exception of executives and international employees. The number of shares eligible for an employee to purchase during each offering period is limited to 750 shares. The purchase price of the stock is 85 percent of the lower closing price of either the first or the last day of the offering period. The ESPP requires a one -year holding period before the stock can be sold. Employees purchased 354 thousand shares at an average price of $28.07 per share during 2015 . Approximately 1.5 million shares were available for purchase under the ESPP at December 31, 2015 . The plan has been suspended effective January 1, 2016. Operating and maintenance expenses and Selling, general and administrative expenses include equity-based compensation expense for the years ended December 31, 2015 , 2014 , and 2013 of $56 million , $44 million , and $37 million , respectively. Income tax benefit recognized related to the stock-based compensation expense for the years ended December 31, 2015 , 2014 , and 2013 was $21 million , $17 million , and $14 million , respectively. Measured but unrecognized stock-based compensation expense at December 31, 2015 , was $65 million , which does not include the effect of estimated forfeitures of $2 million . Unrecognized stock-based compensation expense is comprised of $4 million related to stock options and $61 million related to restricted stock units. These amounts are expected to be recognized over a weighted-average period of 1.9 years. Stock Options Stock options are valued at the date of award, which does not precede the approval date. The purchase price per share for stock options may not be less than the market price of the underlying stock on the date of grant. Stock options generally become exercisable over a three -year period from the date of grant. Stock options generally expire ten years after the grant. The following summary reflects stock option activity and related information for the year ended December 31, 2015 : Stock Options Options Weighted- Average Exercise Price Aggregate Intrinsic Value (Millions) (Millions) Outstanding at December 31, 2014 5.8 $ 25.86 Granted 1.0 $ 49.15 Exercised (1.1 ) $ 19.30 Outstanding at December 31, 2015 5.7 $ 31.51 $ 15 Exercisable at December 31, 2015 4.0 $ 25.52 $ 15 The following table summarizes additional information related to stock option activity during each of the last three years: Years Ended December 31, 2015 2014 2013 (Millions) Total intrinsic value of options exercised $ 37 $ 48 $ 23 Tax benefits realized on options exercised $ 13 $ 18 $ 9 Cash received from the exercise of options $ 20 $ 31 $ 13 The weighted-average remaining contractual life for stock options outstanding and exercisable at December 31, 2015 , was 5.7 years and 4.4 years, respectively. The estimated fair value at date of grant of options for our common stock granted in each respective year, using the Black-Scholes option pricing model, is as follows: 2015 2014 2013 Weighted-average grant date fair value of options for our common stock granted during the year, per share $ 7.61 $ 7.50 $ 5.94 Weighted-average assumptions: Dividend yield 4.8 % 4.2 % 4.3 % Volatility 27.8 % 28.0 % 29.7 % Risk-free interest rate 1.8 % 2.2 % 1.4 % Expected life (years) 6.0 6.5 6.5 The 2015 expected dividend yield is based on the 2015 dividend forecast and the grant-date market price of our stock. Expected volatility is based on the average of our peer group 10 -year historical volatility adjusted by a ratio of our implied volatility to the average of our peer group’s implied volatility. The adjustment is made because the difference in implied volatility between our peer group and us may indicate that we are expected to be more volatile than our peer group average. The risk-free interest rate is based on the U.S. Treasury Constant Maturity rates as of the grant date. The expected life of the option is based on historical exercise behavior and expected future experience. Nonvested Restricted Stock Units The following summary reflects nonvested restricted stock unit activity and related information for the year ended December 31, 2015 . Restricted Stock Units Outstanding Shares Weighted- Average Fair Value (1) (Millions) Nonvested at December 31, 2014 3.6 $ 33.90 Granted 1.4 $ 40.15 Forfeited (0.1 ) $ 36.49 Vested (1.5 ) $ 27.45 Nonvested at December 31, 2015 3.4 $ 39.38 ______________ (1) Performance-based restricted stock units are valued utilizing a Monte Carlo valuation method using measures of total shareholder return. Certain of the performance-based restricted stock units are subject to a holding period of up to two years after the vesting date. Discounts for the restrictions of liquidity were applied to the estimated fair value at the date of the awards and ranged from 5.83 percent to 15.58 percent . The discounts were developed using the Chaffe model and the Finnerty model. All other restricted stock units are valued at the grant-date market price. Restricted stock units generally vest after three years . Value of Restricted Stock Units 2015 2014 2013 Weighted-average grant date fair value of restricted stock units granted during the year, per share $ 40.15 $ 42.79 $ 30.43 Total fair value of restricted stock units vested during the year ($’s in millions) $ 42 $ 27 $ 27 Performance-based restricted stock units granted under the Plan represent 40 percent of nonvested restricted stock units outstanding at December 31, 2015 . These grants may be earned at the end of the vesting period based on actual performance against a performance target. Based on the extent to which certain financial targets are achieved, vested shares may range from zero percent to 500 percent of the original grant amount. WPZ’s Plan Information During 2014, certain employees of ACMP’s general partner received equity-based compensation through ACMP’s equity-based compensation program. The fair value of the awards issued was based on the fair market value of the common units on the date of grant. This value is being amortized over the vesting period, which is one to four years from the date of grant. These awards were converted to WPZ equity-based awards in accordance with the terms of the ACMP Merger. No additional grants of restricted common units were awarded through WPZ’s equity-based compensation programs in 2015, and no additional grants are expected in the future. Equity-based compensation expense of $29 million and $11 million related to WPZ’s equity-based compensation program is included in Operating and maintenance expenses and Selling, general, and administrative expenses for the years ended December 31, 2015 and 2014, respectively. As of December 31, 2015, there was $32 million of unrecognized compensation expense attributable to the outstanding awards, which does not include the effect of estimated forfeitures of $4 million . These amounts are expected to be recognized over a weighted average period of 1.8 years . The following summary reflects nonvested WPZ restricted common unit activity and related information for the year ended December 31, 2015 : Restricted Common Units Outstanding Units Weighted- Average Fair Value (Millions) Nonvested at December 31, 2014 1.3 $ 59.35 Adjustment for unit split in ACMP Merger 0.1 $ — Forfeited (0.1 ) $ 58.05 Vested (0.1 ) $ 59.28 Nonvested at December 31, 2015 1.2 $ 55.93

Fair Value Measurements, Guaran

Fair Value Measurements, Guarantees, and Concentration of Credit Risk	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements, Guarantees, and Concentration of Credit Risk [Text Block]	Note 17 – Fair Value Measurements, Guarantees, and Concentration of Credit Risk The following table presents, by level within the fair value hierarchy, certain of our financial assets and liabilities. The carrying values of cash and cash equivalents, accounts receivable, commercial paper, and accounts payable approximate fair value because of the short-term nature of these instruments. Therefore, these assets and liabilities are not presented in the following table. Fair Value Measurements Using Carrying Amount Fair Value Quoted Prices In Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (Millions) Assets (liabilities) at December 31, 2015: Measured on a recurring basis: ARO Trust investments $ 67 $ 67 $ 67 $ — $ — Energy derivatives assets not designated as hedging instruments 5 5 — 3 2 Energy derivatives liabilities not designated as hedging instruments (2 ) (2 ) — — (2 ) Additional disclosures: Notes receivable and other 12 30 10 2 18 Long-term debt, including current portion (1) (23,987 ) (19,606 ) — (19,606 ) — Guarantee (29 ) (16 ) — (16 ) — Assets (liabilities) at December 31, 2014: Measured on a recurring basis: ARO Trust investments $ 48 $ 48 $ 48 $ — $ — Energy derivatives assets not designated as hedging instruments 3 3 1 — 2 Energy derivatives liabilities not designated as hedging instruments (2 ) (2 ) — — (2 ) Additional disclosures: Notes receivable and other 30 57 — 4 53 Long-term debt, including current portion (1) (20,779 ) (21,131 ) — (21,131 ) — Guarantee (31 ) (27 ) — (27 ) — ___________ (1) Excludes capital leases. The carrying value has been reduced by $123 million and $108 million of debt acquisition costs at December 31, 2015 and 2014, respectively. (See Note 14 – Debt, Banking Arrangements, and Leases .) Fair Value Methods We use the following methods and assumptions in estimating the fair value of our financial instruments: Assets and liabilities measured at fair value on a recurring basis ARO Trust investments : Transco deposits a portion of its collected rates, pursuant to its rate case settlement, into an external trust that is specifically designated to fund future asset retirement obligations. The ARO Trust invests in a portfolio of actively traded mutual funds that are measured at fair value on a recurring basis based on quoted prices in an active market, is classified as available-for-sale, and is reported in Regulatory assets, deferred charges, and other in the Consolidated Balance Sheet. Both realized and unrealized gains and losses are ultimately recorded as regulatory assets or liabilities. Energy derivatives : Energy derivatives include commodity based exchange-traded contracts and over-the-counter (OTC) contracts, which consist of physical forwards, futures, and swaps that are measured at fair value on a recurring basis. The fair value amounts are presented on a gross basis and do not reflect the netting of asset and liability positions permitted under the terms of our master netting arrangements. Further, the amounts do not include cash held on deposit in margin accounts that we have received or remitted to collateralize certain derivative positions. Energy derivatives assets are reported in Other current assets and deferred charges and Regulatory assets, deferred charges, and other in the Consolidated Balance Sheet. Energy derivatives liabilities are reported in Accrued liabilities and Other noncurrent liabilities in the Consolidated Balance Sheet. 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 transfers between Level 1 and Level 2 occurred during the years ended December 31, 2015 or 2014 . Additional fair value disclosures Notes receivable and other: Notes receivable and other consists of various notes, including a receivable related to the sale of certain former Venezuela assets. The disclosed fair value of this receivable is determined by an income approach. We calculated the net present value of a probability-weighted set of cash flows utilizing assumptions based on contractual terms, historical payment patterns by the counterparty, future probabilities of default, our likelihood of using arbitration if the counterparty does not perform, and discount rates. We determined the fair value of the receivable to be $18 million at December 31, 2015 . We began accounting for the receivable under a cost recovery model in first-quarter 2015. Subsequently, we received a payment greater than the carrying amount of the receivable, and as a result, the carrying value of this receivable is zero at December 31, 2015 . We received another payment in January 2016. We have the right to receive two remaining quarterly cash installments of $15 million plus interest. See Note 5 – Investing Activities for interest income associated with this receivable. The current and noncurrent portions of our receivables in 2015 and 2014 are reported in Accounts and notes receivable, Other current assets and deferred charges , and Regulatory assets, deferred charges, and other , respectively, in the Consolidated Balance Sheet. Long-term debt : The disclosed fair value of our long-term debt is determined by a market approach using broker quoted indicative period-end bond prices. The quoted prices are based on observable transactions in less active markets for our debt or similar instruments. Guarantee : The guarantee represented in the table consists of a guarantee we have provided in the event of nonpayment by our previously owned communications subsidiary, Williams Communications Group (WilTel), on a lease performance obligation that extends through 2042. To estimate the disclosed fair value of the guarantee, an estimated default rate is applied to the sum of the future contractual lease payments using an income approach. The estimated default rate is determined by obtaining the average cumulative issuer-weighted corporate default rate based on the credit rating of WilTel’s current owner and the term of the underlying obligation. The default rate is published by Moody’s Investors Service. The carrying value of the guarantee is reported in Accrued liabilities in the Consolidated Balance Sheet. Assets measured at fair value on a nonrecurring basis We performed an interim assessment of the goodwill associated with our Access Midstream reporting unit as of September 30, 2015, and the annual assessment of goodwill associated with our Northeast G&P and West reporting units as of October 1, 2015. No impairment charges were required following these evaluations. During the fourth quarter of 2015, we observed a significant decline in the market values of WPZ and comparable midstream companies within the industry. This served to reduce our estimate of enterprise value and increased our estimates of discount rates. As a result, we performed an impairment assessment as of December 31, 2015, of the goodwill associated with these reporting units, all within the Williams Partners segment. We estimated the fair value of each reporting unit based on an income approach utilizing discount rates specific to the underlying businesses of each reporting unit. These discount rates considered variables unique to each business area, including equity yields of comparable midstream businesses, expectations for future growth, and customer performance considerations. Weighted-average discount rates utilized ranged from approximately 10 percent to 13 percent across the three reporting units. As a result of the increases in discount rates during the fourth quarter, coupled with certain reductions in estimated future cash flows determined during the same period, the fair values of the Access Midstream and Northeast G&P reporting units were determined to be below their respective carrying values. For these measurements, the book basis of each reporting unit was reduced by the associated deferred tax liabilities. We then calculated the implied fair value of goodwill by performing a hypothetical application of the acquisition method wherein the estimated fair value was allocated to the underlying assets and liabilities of each reporting unit. As a result of these level 3 measurements, we determined that the previously recorded goodwill associated with each reporting unit was fully impaired, resulting in a fourth quarter noncash charge of $1,098 million . For the West reporting unit, the estimated fair value significantly exceeded the carrying value and no impairment was recorded. Impairments Years Ended December 31, Date of Measurement Fair Value 2015 2014 (Millions) Impairment of certain assets (1) June 30, 2014 $ 46 $ 17 Impairment of certain assets (1) December 31, 2014 32 13 Impairment of certain assets (1) June 30, 2015 17 $ 20 Impairment of certain assets (2) December 31, 2014 1 12 Impairment of certain assets (3) December 31, 2015 13 94 Impairment of certain assets (4) December 31, 2015 40 64 Level 3 fair value measurements of certain assets 178 42 Other impairments (5) 31 10 Total impairments of certain assets $ 209 $ 52 ______________ (1) Reflects impairment charges for our Williams Partners segment associated with certain surplus equipment. Certain of these assets were previously presented as held for sale, but are now considered held for use and reported in Property, plant, and equipment – net in the Consolidated Balance Sheet at December 31, 2015. The estimated fair value was determined by a market approach based on our analysis of observable inputs in the principal market. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations . (2) Reflects impairment charges for our Williams Partners segment associated with certain surplus equipment considered held for sale and reported in Other current assets and deferred charges in the Consolidated Balance Sheet . The estimated fair value was determined by a market approach based on our analysis of observable inputs in the principal market. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations . (3) Reflects an impairment charge within our Williams Partners segment associated with previously capitalized project development costs for a gas processing plant, the completion of which is now considered remote due to unfavorable impact of low natural gas prices on customer drilling activities. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations .The assessed fair value primarily represents the estimated salvage value of certain equipment measured using a market approach based on our analysis of observable inputs in the principal market and is reported in Property, plant, and equipment – net in the Consolidated Balance Sheet. (4) Reflects an impairment charge within our Williams NGL & Petchem Services segment associated with previously capitalized project development costs for an olefins pipeline project, the completion of which is now considered remote due to the lack of customer interest. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations . The assessed fair value primarily represents the estimated value of unused pipeline measured using a market approach based on our analysis of observable inputs in the principal market and is reported in Property, plant, and equipment – net in the Consolidated Balance Sheet. (5) Reflects multiple individually insignificant impairments of other certain assets that may no longer be in use or are surplus in nature for which the fair value was determined to be zero or an insignificant salvage value. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations . Date of Measurement Fair Value Impairments (Millions) Impairments of equity-method investments (1) September 30, 2015 $ 1,203 $ 461 Impairments of equity-method investments (2) December 31, 2015 4,017 890 Other impairment of equity-method investment December 31, 2015 58 8 Level 3 fair value measurements of equity-method investments $ 1,359 ______________ (1) Reflects other-than-temporary impairment charges related to Williams Partners’ equity-method investments in the Delaware basin gas gathering system and certain of the Appalachia Midstream Investments reflected within Impairment of equity-method investments in the Consolidated Statement of Operations . The historical carrying value of these investments was initially recorded based on estimated fair value during the third quarter of 2014 in conjunction with the ACMP Acquisition. We estimated the fair value of these investments using an income approach based on expected future cash flows and appropriate discount rates. The determination of estimated future cash flows involved significant assumptions regarding gathering volumes and related capital spending. Discount rates utilized were 11.8 percent and 8.8 percent for the Delaware basin gas gathering system and certain of the Appalachia Midstream Investments, respectively, and reflected our cost of capital as impacted by market conditions, and risks associated with the underlying businesses. (2) Reflects other-than-temporary impairment charges related to Williams Partners’ equity-method investments in the Delaware basin gas gathering system, certain of the Appalachia Midstream Investments, UEOM, and Laurel Mountain, reflected within Impairment of equity-method investments in the Consolidated Statement of Operations . We estimated the fair value of these investments using an income approach based on expected future cash flows and appropriate discount rates. The determination of estimated future cash flows involved significant assumptions regarding gathering volumes and related capital spending. Discount rates utilized ranged from 10.8 percent to 14.4 percent and reflected further fourth quarter increases in our cost of capital, revised estimates of expected future cash flows, and risks associated with the underlying businesses. During the first quarter of 2016, we have observed further significant decline in the market value of WPZ’s publicly traded equity. Continuation of this condition and/or further decline in such value will likely require the evaluation of certain of our equity investments for potential impairment at March 31, 2016, including those that were impaired at December 31, 2015. As a result, there is the potential for significant additional noncash impairments of our investments in the future. Guarantees We are required by our revolving credit agreements to indemnify lenders for certain taxes required to be withheld from payments due to the lenders and for certain 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. Regarding our previously described guarantee of WilTel’s lease performance, the maximum potential undiscounted exposure is approximately $33 million at December 31, 2015 . Our exposure declines systematically throughout the remaining term of WilTel’s obligation. Concentration of Credit Risk Cash equivalents Our cash equivalents are primarily invested in funds with high-quality, short-term securities and instruments that are issued or guaranteed by the U.S. government. Accounts and notes receivable The following table summarizes concentration of receivables, net of allowances. December 31, 2015 2014 (Millions) NGLs, natural gas, and related products and services $ 823 $ 730 Transportation of natural gas and related products 202 175 Income tax receivable 7 167 Other 9 67 Total $ 1,041 $ 1,139 Customers include producers, distribution companies, industrial users, gas marketers and pipelines primarily located in the continental United States and Canada. As a general policy, collateral is not required for receivables, but customers’ financial condition and credit worthiness are evaluated regularly. As of December 31, 2015 and 2014, Chesapeake Energy Corporation, and its affiliates, a customer within our Williams Partners segment, accounted for $364 million and $308 million , respectively, of the consolidated Accounts and notes receivable balance. Of this receivable at December 31, 2015, $198 million relates to annual minimum volume commitment fees that were subsequently collected in February 2016. Revenues In 2015 and 2014, Chesapeake Energy Corporation, and its affiliates, a customer within our Williams Partners segment, accounted for 18 percent and 9 percent , respectively, of our consolidated revenues.

Contingent Liabilities and Comm

Contingent Liabilities and Commitments	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Contingent Liabilities [Text Block]	Note 18 – Contingent Liabilities and Commitments Reporting of Natural Gas-Related Information to Trade Publications Direct and indirect purchasers of natural gas in various states filed class actions against us, our former affiliate WPX and its subsidiaries, and others alleging the manipulation of published gas price indices and seeking unspecified amounts of damages. Such actions were transferred to the Nevada federal district court for consolidation of discovery and pre-trial issues. We have agreed to indemnify WPX and its subsidiaries related to this matter. Because of the uncertainty around the remaining pending unresolved issues, including an insufficient description of the purported classes and other related matters, we cannot reasonably estimate a range of potential exposure at this time. However, it is reasonably possible that the ultimate resolution of these actions and our related indemnification obligation could result in future charges that may be material to our results of operations. In connection with this indemnification, we have an accrued liability balance associated with this matter, and as a result, have exposure to future developments in this matter. Geismar Incident As a result of the previously discussed Geismar Incident, there were two fatalities and numerous individuals (including employees and contractors) reported injuries, which varied from minor to serious. We are addressing the following matters in connection with the Geismar Incident. On October 21, 2013, the EPA issued an Inspection Report pursuant to the Clean Air Act’s Risk Management Program following its inspection of the facility on June 24 through June 28, 2013. The report notes the EPA’s preliminary determinations about the facility’s documentation regarding process safety, process hazard analysis, as well as operating procedures, employee training, and other matters. On June 16, 2014, we received a request for information related to the Geismar Incident from the EPA under Section 114 of the Clean Air Act to which we responded on August 13, 2014. The EPA could issue penalties pertaining to final determinations. Multiple lawsuits, including class actions for alleged offsite impacts, property damage, customer claims, and personal injury, have been filed against us. To date, we have settled certain of the personal injury claims for an aggregate immaterial amount that we have recovered from our insurers. The trial for certain plaintiffs claiming personal injury, that was set to begin on June 15, 2015, in Iberville Parish, Louisiana, has been postponed to September 6, 2016. We believe it is probable that additional losses will be incurred on some lawsuits, while for others we believe it is only reasonably possible that losses will be incurred. However, due to ongoing litigation involving defenses to liability, the number of individual plaintiffs, limited information as to the nature and extent of all plaintiffs’ damages, and the ultimate outcome of all appeals, we are unable to reliably estimate any such losses at this time. We believe that it is probable that any ultimate losses incurred will be covered by our general liability insurance policy, which has an aggregate limit of $610 million applicable to this event and retention (deductible) of $2 million per occurrence. Alaska Refinery Contamination Litigation In 2010, James West filed a class action lawsuit in state court in Fairbanks, Alaska on behalf of individual property owners whose water contained sulfolane contamination allegedly emanating from the Flint Hills Oil Refinery in North Pole, Alaska. The suit named our subsidiary, Williams Alaska Petroleum Inc. (WAPI), and Flint Hills Resources Alaska, LLC (FHRA), a subsidiary of Koch Industries, Inc., as defendants. We owned and operated the refinery until 2004 when we sold it to FHRA. We and FHRA made claims under the pollution liability insurance policy issued in connection with the sale of the North Pole refinery to FHRA. We and FHRA also filed claims against each other seeking, among other things, contractual indemnification alleging that the other party caused the sulfolane contamination. In 2011, we and FHRA settled the James West claim. We and FHRA subsequently filed motions for summary judgment on the other’s claims. On July 8, 2014, the court dismissed all FHRA’s claims and entered judgment for us. On August 6, 2014, FHRA appealed the court’s decision to the Alaska Supreme Court, which heard oral arguments in October of 2015. The Supreme Court’s decision is expected this spring. We currently estimate that our reasonably possible loss exposure in this matter could range from an insignificant amount up to $32 million , although uncertainties inherent in the litigation process, expert evaluations, and jury dynamics might cause our exposure to exceed that amount. On March 6, 2014, the State of Alaska filed suit against FHRA, WAPI, and us in state court in Fairbanks seeking injunctive relief and damages in connection with sulfolane contamination of the water supply near the Flint Hills Oil Refinery in North Pole, Alaska. On May 5, 2014, FHRA filed cross-claims against us in the State of Alaska suit. FHRA also seeks injunctive relief and damages. On November 26, 2014, the City of North Pole (North Pole) filed suit in Alaska state court in Fairbanks against FHRA, WAPI, and us alleging nuisance and violations of municipal and state statutes based upon the same alleged sulfolane contamination of the water supply. North Pole claims an unspecified amount of past and future damages as well as punitive damages against WAPI. FHRA filed cross-claims against us. In October of 2015, the Court consolidated the State of Alaska and North Pole cases. To our knowledge, exposure in these cases is duplicative of the reasonable loss exposure in the James West case. Independent of the litigation matter described in the preceding paragraphs, in 2013, the Alaska Department of Environmental Conservation indicated that it views FHRA and us as responsible parties, and that it intended to enter a compliance order to address the environmental remediation of sulfolane and other possible contaminants including cleanup work outside the refinery’s boundaries. Due to the ongoing assessment of the level and extent of sulfolane contamination and the ultimate cost of remediation and division of costs among the potentially responsible parties, we are unable to estimate a range of exposure at this time. Shareholder Litigation In July 2015, a purported stockholder of us filed a putative class and derivative action on behalf of us in the Court of Chancery of the State of Delaware. The action names as defendants certain members of our Board of Directors as well as WPZ, and names us as a nominal defendant. On December 4, 2015, the plaintiff filed an amended complaint for such action, alleging that the preliminary proxy statement filed in connection with our proposed merger with Energy Transfer is false and misleading. As relief, the complaint requests, among other things, an injunction requiring us to make supplemental disclosures and an award of costs and attorneys’ fees. On December 9, 2015, we moved to dismiss the amended complaint. We cannot reasonably estimate a range of potential loss at this time. Between October 5, 2015 and January 19, 2016, purported stockholders of us filed seven putative class action lawsuits in the Delaware Court of Chancery, one suit in U.S. District Court in Delaware, and one suit in U.S. District Court in Oklahoma, each challenging our proposed merger with Energy Transfer. The complaints assert various claims against the individual members of our Board of Directors, certain entities affiliated with Energy Transfer (the “ETE defendants”), and us. The allegations include claims that our Board of Directors breached its fiduciary duties to our stockholders by agreeing to sell us through an allegedly unfair process and for an allegedly unfair price, that the ETE defendants and/or we aided and abetted this purported breach of fiduciary duties, and that our directors violated their fiduciary duties by allegedly failing to disclose material information about the merger. Two lawsuits also claim that disclosures about the merger violate federal securities laws and our Directors, we, and ETE defendants are liable for such violations. The complaints seek, among other things, an injunction against the merger and an award of costs and attorneys’ fees. We cannot reasonably estimate a range of potential loss at this time. Royalty Matters Certain of our customers, including one major customer, have been named in various lawsuits alleging underpayment of royalties and claiming, among other things, violations of anti-trust laws and the Racketeer Influenced and Corrupt Organizations Act. We have also been named as a defendant in certain of these cases in Texas, Pennsylvania, and Ohio based on allegations that we improperly participated with that major customer in causing the alleged royalty underpayments. We have also received subpoenas from the United States Department of Justice and the Pennsylvania Attorney General requesting documents relating to the agreements between us and our major customer and calculations of the major customer’s royalty payments. On December 9, 2015, the Pennsylvania Attorney General filed a civil suit against one of our major customers and us alleging breaches of the Pennsylvania Unfair Trade Practices and Consumer Protection Law, and on February 8, 2016, the Pennsylvania Attorney General filed an amended complaint in such civil suit, which omitted us as a party. We believe that the claims asserted are subject to indemnity obligations owed to us by that major customer. Due to the preliminary status of the cases, we are unable to estimate a range of liability at this time. Environmental Matters We are a participant in certain environmental activities in various stages including assessment studies, cleanup operations, and remedial processes at certain sites, some of which we currently do not own. We are monitoring these sites in a coordinated effort with other potentially responsible parties, the EPA, and other governmental authorities. We are jointly and severally liable along with unrelated third parties in some of these activities and solely responsible in others. Certain of our subsidiaries have been identified as potentially responsible parties at various Superfund and state waste disposal sites. In addition, these subsidiaries have incurred, or are alleged to have incurred, various other hazardous materials removal or remediation obligations under environmental laws. As of December 31, 2015 , we have accrued liabilities totaling $40 million for these matters, as discussed below. Our accrual reflects the most likely costs of cleanup, which are generally based on completed assessment studies, preliminary results of studies, or our experience with other similar cleanup operations. Certain assessment studies are still in process for which the ultimate outcome may yield significantly different estimates of most likely costs. Any incremental amount in excess of amounts currently accrued cannot be reasonably estimated at this time due to uncertainty about the actual number of contaminated sites ultimately identified, the actual amount and extent of contamination discovered, and the final cleanup standards mandated by the EPA and other governmental authorities. The EPA and various state regulatory agencies routinely promulgate and propose new rules, and issue updated guidance to existing rules. More recent rules and rulemakings include, but are not limited to, rules for reciprocating internal combustion engine maximum achievable control technology, new air quality standards for one hour nitrogen dioxide emission limits, and new air quality standards impacting storage vessels, pressure valves, and compressors. On October 1, 2015, the EPA issued its new rule regarding National Ambient Air Quality Standards for ground-level ozone, setting a new standard of 70 parts per billion. We are monitoring the rule’s implementation and evaluating potential impacts to our operations. For these and other new regulations, we are unable to estimate the costs of asset additions or modifications necessary to comply due to uncertainty created by the various legal challenges to these regulations and the need for further specific regulatory guidance. Continuing operations Our interstate gas pipelines are involved in remediation activities related to certain facilities and locations for polychlorinated biphenyls, mercury, and other hazardous substances. These activities have involved the EPA and various state environmental authorities, resulting in our identification as a potentially responsible party at various Superfund waste sites. At December 31, 2015 , we have accrued liabilities of $8 million for these costs. We expect that these costs will be recoverable through rates. We also accrue environmental remediation costs for natural gas underground storage facilities, primarily related to soil and groundwater contamination. At December 31, 2015 , we have accrued liabilities totaling $7 million for these costs. Former operations, including operations classified as discontinued We have potential obligations in connection with assets and businesses we no longer operate. These potential obligations include remediation activities at the direction of federal and state environmental authorities and the indemnification of the purchasers of certain of these assets and businesses for environmental and other liabilities existing at the time the sale was consummated. Our responsibilities relate to the operations of the assets and businesses described below. • Former agricultural fertilizer and chemical operations and former retail petroleum and refining operations; • Former petroleum products and natural gas pipelines; • Former petroleum refining facilities; • Former exploration and production and mining operations; • Former electricity and natural gas marketing and trading operations. At December 31, 2015 , we have accrued environmental liabilities of $25 million related to these matters. Other Divestiture Indemnifications Pursuant to various purchase and sale agreements relating to divested businesses and assets, we have indemnified certain purchasers against liabilities that they may incur with respect to the businesses and assets acquired from us. The indemnities provided to the purchasers are customary in sale transactions and are contingent upon the purchasers incurring liabilities that are not otherwise recoverable from third parties. The indemnities generally relate to breach of warranties, tax, historic litigation, personal injury, property damage, environmental matters, right of way, and other representations that we have provided. At December 31, 2015 , other than as previously disclosed, we are not aware of any material claims against us involving the indemnities; thus, we do not expect any of the indemnities provided pursuant to the sales agreements to have a material impact on our future financial position. Any claim for indemnity brought against us in the future may have a material adverse effect on our results of operations in the period in which the claim is made. In addition to the foregoing, various other proceedings are pending against us which are incidental to our operations. Summary We have disclosed our estimated range of reasonably possible losses for certain matters above, as well as all significant matters for which we are unable to reasonably estimate a range of possible loss. We estimate that for all other matters for which we are able to reasonably estimate a range of loss, our aggregate reasonably possible losses beyond amounts accrued are immaterial to our expected future annual results of operations, liquidity, and financial position. These calculations have been made without consideration of any potential recovery from third parties. Commitments Commitments for construction and acquisition of property, plant, and equipment are approximately $770 million at December 31, 2015 .

Segment Disclosures

Segment Disclosures	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment Disclosures [Text Block]	Note 19 – Segment Disclosures Our reportable segments are Williams Partners and Williams NGL & Petchem Services. All remaining business activities are included in Other. (See Note 1 – General, Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies .) Our segment presentation of Williams Partners, which includes our consolidated master limited partnership, is reflective of the parent-level focus by our chief operating decision-maker, considering the resource allocation and governance provisions associated with the master limited partnership structure. This partnership maintains capital and cash management structures that are separate from ours. It is self-funding and maintains its own lines of bank credit and cash management accounts. These factors, coupled with different costs of capital from our other businesses, serve to differentiate the management of this entity as a whole. Performance Measurement Prior to first quarter of 2015, we evaluated segment operating performance based on Segment profit (loss) from operations. Beginning in the first quarter of 2015, we evaluate segment operating performance based upon Modified EBITDA (earnings before interest, taxes, depreciation, and amortization). This measure represents the basis of our internal financial reporting and is the primary performance measure used by our chief operating decision maker in measuring performance and allocating resources among our reportable segments. Prior period segment disclosures have been recast to reflect this change. We define Modified EBITDA as follows: • Net income (loss) before: ◦ Income (loss) from discontinued operations; ◦ Provision (benefit) for income taxes; ◦ Interest incurred, net of interest capitalized; ◦ Equity earnings (losses); ◦ Gain on remeasurement of equity-method investment; ◦ Impairment of equity-method investments; ◦ Other investing income (loss) – net; ◦ Impairment of goodwill; ◦ Depreciation and amortization expenses; ◦ Accretion expense associated with asset retirement obligations for nonregulated operations. • This measure is further adjusted to include our proportionate share (based on ownership interest) of Modified EBITDA from our equity-method investments calculated consistently with the definition described above. The following geographic area data includes Revenues from external customers based on product shipment origin and Long-lived assets based upon physical location. United States Canada Total (Millions) Revenues from external customers: 2015 $ 7,247 $ 113 $ 7,360 2014 7,229 408 7,637 2013 6,703 157 6,860 Long-lived assets: 2015 $ 38,016 $ 1,580 $ 39,596 2014 38,290 1,364 39,654 2013 19,260 1,240 20,500 Long-lived assets are comprised of property, plant, and equipment, goodwill, and other intangible assets. The following table reflects the reconciliation of Segment revenues to Total revenues as reported in the Consolidated Statement of Operations and Other financial information . Williams Partners Williams NGL & Petchem Services (1) Other Eliminations Total (Millions) 2015 Segment revenues: Service revenues External $ 5,134 $ 2 $ 28 $ — $ 5,164 Internal 1 — 158 (159 ) — Total service revenues 5,135 2 186 (159 ) 5,164 Product sales External 2,196 — — — 2,196 Internal — — — — — Total product sales 2,196 — — — 2,196 Total revenues $ 7,331 $ 2 $ 186 $ (159 ) $ 7,360 Other financial information: Additions to long-lived assets $ 2,960 $ 360 $ 28 $ (12 ) $ 3,336 Proportional Modified EBITDA of equity-method investments 699 — — 699 2014 Segment revenues: Service revenues External $ 3,887 $ — $ 229 $ — $ 4,116 Internal 1 — 30 (31 ) — Total service revenues 3,888 — 259 (31 ) 4,116 Product sales External 3,521 — — — 3,521 Internal — — — — — Total product sales 3,521 — — — 3,521 Total revenues $ 7,409 $ — $ 259 $ (31 ) $ 7,637 Other financial information: Additions to long-lived assets (2) $ 20,413 $ 291 $ 54 $ (2 ) $ 20,756 Proportional Modified EBITDA of equity-method investments 431 (78 ) 85 438 2013 Segment revenues: Service revenues External $ 2,914 $ — $ 25 $ — $ 2,939 Internal — — 11 (11 ) — Total service revenues 2,914 — 36 (11 ) 2,939 Product sales External 3,921 — — — 3,921 Internal — — — — — Total product sales 3,921 — — — 3,921 Total revenues $ 6,835 $ — $ 36 $ (11 ) $ 6,860 Other financial information: Additions to long-lived assets $ 3,409 $ 295 $ 27 $ — $ 3,731 Proportional Modified EBITDA of equity-method investments 209 — 197 406 __________ (1) Includes certain projects under development and thus nominal reported revenues to date. (2) 2014 Additions to long-lived assets within our Williams Partners segment primarily includes the acquisition-date fair value of long-lived assets from the ACMP Acquisition. (See Note 2 - Acquisitions.) The following table reflects the reconciliation of Modified EBITDA to Net income (loss) as reported in the Consolidated Statement of Operations . Years Ended December 31, 2015 2014 2013 (Millions) Modified EBITDA by segment: Williams Partners $ 4,003 $ 3,244 $ 2,447 Williams NGL & Petchem Services (83 ) (115 ) (33 ) Other (29 ) 103 197 3,891 3,232 2,611 Accretion expense associated with asset retirement obligations for nonregulated operations (28 ) (18 ) (15 ) Depreciation and amortization expenses (1,738 ) (1,176 ) (815 ) Impairment of goodwill (1,098 ) — — Equity earnings (losses) 335 144 134 Gain on remeasurement of equity-method investment — 2,544 — Impairment of equity-method investments (1,359 ) — — Other investing income (loss) – net 27 43 81 Proportional Modified EBITDA of equity-method investments (699 ) (438 ) (406 ) Interest expense (1,044 ) (747 ) (510 ) (Provision) benefit for income taxes 399 (1,249 ) (401 ) Income (loss) from discontinued operations, net of tax — 4 (11 ) Net income (loss) $ (1,314 ) $ 2,339 $ 668 The following table reflects Total assets and Equity-method investments by reportable segments: Total Assets Equity-Method Investments December 31, 2015 December 31, 2014 December 31, 2015 December 31, 2014 (Millions) Williams Partners $ 47,870 $ 49,248 $ 7,336 $ 8,399 Williams NGL & Petchem Services 835 612 — — Other 850 1,186 — 1 Eliminations (535 ) (591 ) — — Total $ 49,020 $ 50,455 $ 7,336 $ 8,400

Schedule I Condensed Financial

Schedule I Condensed Financial Information Of Registrant	12 Months Ended
	Dec. 31, 2015
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Financial Information of Parent Company Only Disclosure [Text Block]	The Williams Companies, Inc. Schedule I — Condensed Financial Information of Registrant Statement of Comprehensive Income (Loss) (Parent) Years Ended December 31, 2015 2014 2013 (Millions, except per-share amounts) Equity in earnings of consolidated subsidiaries $ 232 $ 1,799 $ 1,564 Equity earnings (losses) from investment in Access Midstream Partners — (7 ) 30 Interest incurred — external (255 ) (206 ) (156 ) Interest incurred — affiliate (828 ) (797 ) (722 ) Interest income — affiliate 6 10 71 Gain on remeasurement of equity-method investment — 2,544 — Other income (expense) — net (75 ) (13 ) 32 Income (loss) from continuing operations before income taxes (920 ) 3,330 819 Provision (benefit) for income taxes (349 ) 1,220 378 Income (loss) from continuing operations (571 ) 2,110 441 Income (loss) from discontinued operations — 4 (11 ) Net income (loss) $ (571 ) $ 2,114 $ 430 Basic earnings (loss) per common share: Income (loss) from continuing operations $ (.76 ) $ 2.93 $ .65 Income (loss) from discontinued operations — .01 (.02 ) Net income (loss) $ (.76 ) $ 2.94 $ .63 Weighted-average shares (thousands) 749,271 719,325 682,948 Diluted earnings (loss) per common share: Income (loss) from continuing operations $ (.76 ) $ 2.91 $ .64 Income (loss) from discontinued operations — .01 (.02 ) Net income (loss) $ (.76 ) $ 2.92 $ .62 Weighted-average shares (thousands) 749,271 723,641 687,185 Other comprehensive income (loss): Equity in other comprehensive income (loss) of consolidated subsidiaries $ (204 ) $ (96 ) $ (41 ) Other comprehensive income (loss) attributable to The Williams Companies, Inc. 33 (80 ) 239 Other comprehensive income (loss) (171 ) (176 ) 198 Less: Other comprehensive income (loss) attributable to noncontrolling interests (70 ) (19 ) — Comprehensive income (loss) attributable to The Williams Companies, Inc. $ (672 ) $ 1,957 $ 628 See accompanying notes. The Williams Companies, Inc. Schedule I — Condensed Financial Information of Registrant – (Continued) Balance Sheet (Parent) December 31, 2015 2014 (Millions) ASSETS Current assets: Cash and cash equivalents $ 12 $ 49 Other current assets and deferred charges 62 246 Total current assets 74 295 Investments in and advances to consolidated subsidiaries 30,927 31,405 Property, plant, and equipment — net 99 99 Other noncurrent assets 12 12 Total assets $ 31,112 $ 31,811 LIABILITIES AND STOCKHOLDERS’ EQUITY Current liabilities: Accounts payable $ 27 $ 27 Other current liabilities 163 174 Total current liabilities 190 201 Long-term debt 4,811 4,528 Notes payable — affiliates 15,506 13,295 Pension, other postretirement, and other noncurrent liabilities 336 409 Deferred income tax liabilities 4,121 4,601 Contingent liabilities and commitments Equity: Common stock 784 782 Other stockholders’ equity 5,364 7,995 Total stockholders’ equity 6,148 8,777 Total liabilities and stockholders’ equity $ 31,112 $ 31,811 See accompanying notes. The Williams Companies, Inc. Schedule I — Condensed Financial Information of Registrant – (Continued) Statement of Cash Flows (Parent) Years Ended December 31, 2015 2014 2013 (Millions) NET CASH FLOWS PROVIDED (USED) BY OPERATING ACTIVITIES $ (1,209 ) $ (500 ) $ 19 FINANCING ACTIVITIES: Proceeds from long-term debt 2,097 2,935 — Payments of long-term debt (1,817 ) (671 ) (1 ) Changes in notes payable to affiliates 2,211 2,465 1,892 Tax benefit of stock-based awards — 25 19 Proceeds from issuance of common stock 27 3,416 18 Dividends paid (1,836 ) (1,412 ) (982 ) Other — net (2 ) (17 ) (3 ) Net cash provided (used) by financing activities 680 6,741 943 INVESTING ACTIVITIES: Capital expenditures (29 ) (54 ) (23 ) Purchase of Access Midstream Partners — (5,995 ) — Changes in investments in and advances to consolidated subsidiaries 521 (450 ) (985 ) Other — net — 25 (12 ) Net cash provided (used) by investing activities 492 (6,474 ) (1,020 ) Increase (decrease) in cash and cash equivalents (37 ) (233 ) (58 ) Cash and cash equivalents at beginning of year 49 282 340 Cash and cash equivalents at end of year $ 12 $ 49 $ 282 See accompanying notes. Note 1. Guarantees In addition to the guarantees disclosed in the accompanying consolidated financial statements in Item 8, we have financially guaranteed the performance of certain consolidated subsidiaries. The duration of these guarantees varies, and we estimate the maximum undiscounted potential future payment obligation related to these guarantees as of December 31, 2015, is approximately $631 million . Note 2. Cash Dividends Received We receive dividends and distributions either directly from our subsidiaries or indirectly through dividends received by subsidiaries and subsequent transfers of cash to us through our corporate cash management system. The total of such receipts ultimately related to dividends and distributions for the years ended December 31, 2015, 2014, and 2013 was approximately $1.8 billion , $1.9 billion , and $1.5 billion , respectively.

Schedule II Valuation and Quali

Schedule II Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2015
Valuation and Qualifying Accounts [Abstract]
Schedule II Valuation and Qualifying Accounts [Text Block]	The Williams Companies, Inc. Schedule II — Valuation and Qualifying Accounts Additions Beginning Balance Charged (Credited) To Costs and Expenses Other Deductions Ending Balance (Millions) 2015 Allowance for doubtful accounts — accounts and notes receivable (1) $ — $ 3 $ — $ — $ 3 Deferred tax asset valuation allowance (1) 206 (16 ) — — 190 2014 Allowance for doubtful accounts — accounts and notes receivable (1) — — — — — Deferred tax asset valuation allowance (1) 181 25 — — 206 2013 Allowance for doubtful accounts — accounts and notes receivable (1) — — — — — Deferred tax asset valuation allowance (1) 144 37 — — 181 __________ (1) Deducted from related assets.

General, Description of Busin30

General, Description of Business, Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Principles of consolidation [Policy Text Block]	Principles of consolidation The consolidated financial statements include the accounts of all entities that we control and our proportionate interest in the accounts of certain ventures in which we own an undivided interest. Management’s judgment is required to evaluate whether we control an entity. Key areas of that evaluation include: • Determining whether an entity is a variable interest entity (VIE); • Determining whether we are the primary beneficiary of a VIE, including evaluating which activities of the VIE most significantly impact its economic performance and the degree of power that we and our related parties have over those activities through our variable interests; • Identifying events that require reconsideration of whether an entity is a VIE and continuously evaluating whether we are a VIE’s primary beneficiary; • Evaluating whether other owners in entities that are not VIEs are able to effectively participate in significant decisions that would be expected to be made in the ordinary course of business such that we do not have the power to control such entities. We apply the equity method of accounting to investments over which we exercise significant influence but do not control.
Equity-method investment basis differences [Policy Text Block]	Equity-method investment basis differences Differences between the cost of our equity-method investments and our underlying equity in the net assets of investees are accounted for as if the investees were consolidated subsidiaries. Equity earnings (losses) in the Consolidated Statement of Operations includes our allocable share of net income (loss) of investees adjusted for any depreciation and amortization, as applicable, associated with basis differences.
Use of estimates [Policy Text Block]	Use of estimates 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. Significant estimates and assumptions include: • Impairment assessments of investments, property, plant, and equipment, goodwill, and other identifiable intangible assets; • Litigation-related contingencies; • Environmental remediation obligations; • Realization of deferred income tax assets; • Depreciation and/or amortization of equity-method investment basis differences; • Asset retirement obligations; • Pension and postretirement valuation variables; • Acquisition related purchase price allocations. These estimates are discussed further throughout these notes.
Regulatory Accounting [Policy Text Block]	Regulatory accounting Transco and Northwest Pipeline are regulated by the Federal Energy Regulatory Commission (FERC). Their rates, which are established by the FERC, are designed to recover the costs of providing the regulated services, and their competitive environment makes it probable that such rates can be charged and collected. Therefore, our management has determined that it is appropriate under Accounting Standards Codification (ASC) Topic 980, “Regulated Operations,” to account for and report regulatory assets and liabilities related to these operations consistent with the economic effect of the way in which their rates are established. Accounting for these operations that are regulated can differ from the accounting requirements for nonregulated operations. For example, for regulated operations, allowance for funds used during construction (AFUDC) represents the estimated cost of debt and equity funds applicable to utility plant in process of construction and is capitalized as a cost of property, plant, and equipment because it constitutes an actual cost of construction under established regulatory practices; nonregulated operations are only allowed to capitalize the cost of debt funds related to construction activities, while a component for equity is prohibited. The components of our regulatory assets and liabilities relate to the effects of deferred taxes on equity funds used during construction, asset retirement obligations, fuel cost differentials, levelized incremental depreciation, negative salvage, and pension and other postretirement benefits. Our current and noncurrent regulatory asset and liability balances for the years ended December 31, 2015 and 2014 are as follows: December 31, 2015 2014 (Millions) Current assets reported within Other current assets and deferred charges $ 84 $ 81 Noncurrent assets reported within Regulatory assets, deferred charges, and other 370 337 Total regulated assets $ 454 $ 418 Current liabilities reported within Accrued liabilities $ 4 $ 11 Noncurrent liabilities reported within Other noncurrent liabilities 434 375 Total regulated liabilities $ 438 $ 386
Cash and cash equivalents [Policy Text Block]	Cash and cash equivalents Cash and cash equivalents in the Consolidated Balance Sheet includes amounts primarily invested in funds with high-quality, short-term securities and instruments that are issued or guaranteed by the U.S. government. These have maturity dates of three months or less when acquired.
Accounts receivable [Policy Text Block]	Accounts receivable Accounts receivable are carried on a gross basis, with no discounting, less an allowance for doubtful accounts. We estimate the allowance for doubtful accounts based on existing economic conditions, the financial condition of our customers, and the amount and age of past due accounts. We consider receivables past due if full payment is not received by the contractual due date. Interest income related to past due accounts receivable is generally recognized at the time full payment is received or collectability is assured. Past due accounts are generally written off against the allowance for doubtful accounts only after all collection attempts have been exhausted.
Inventory valuation [Policy Text Block]	Inventory valuation All Inventories in the Consolidated Balance Sheet are stated at the lower of cost or market. The cost of inventories is primarily determined using the average-cost method.
Property, plant, and equipment [Policy Text Block]	Property, plant, and equipment Property, plant, and equipment is recorded at cost. We base the carrying value of these assets on estimates, assumptions, and judgments relative to capitalized costs, useful lives, and salvage values. As regulated entities, Northwest Pipeline and Transco provide for depreciation using the straight-line method at FERC-prescribed rates. Depreciation for nonregulated entities is provided primarily on the straight-line method over estimated useful lives, except for certain offshore facilities that apply an accelerated depreciation method. Gains or losses from the ordinary sale or retirement of property, plant, and equipment for regulated pipelines are credited or charged to accumulated depreciation. Other gains or losses are recorded in Other (income) expense – net included in Operating income (loss) in the Consolidated Statement of Operations . Ordinary maintenance and repair costs are generally expensed as incurred. Costs of major renewals and replacements are capitalized as property, plant, and equipment. We record a liability and increase the basis in the underlying asset for the present value of each expected future asset retirement obligation (ARO) at the time the liability is initially incurred, typically when the asset is acquired or constructed. As regulated entities, Northwest Pipeline and Transco offset the depreciation of the underlying asset that is attributable to capitalized ARO cost to a regulatory asset as management expects to recover these amounts in future rates. We measure changes in the liability due to passage of time by applying an interest rate to the liability balance. This amount is recognized as an increase in the carrying amount of the liability and as a corresponding accretion expense included in Operating and maintenance expenses in the Consolidated Statement of Operations , except for regulated entities, for which the liability is offset by a regulatory asset. The regulatory asset is amortized commensurate with our collection of those costs in rates. Measurements of AROs include, as a component of future expected costs, an estimate of the price that a third party would demand, and could expect to receive, for bearing the uncertainties inherent in the obligations, sometimes referred to as a market-risk premium.
Goodwill [Policy Text Block]	Goodwill Goodwill in the Consolidated Balance Sheet represents the excess of the consideration plus the fair value of any noncontrolling interest or any previously held equity interest, over the fair value of the net assets acquired. It is not subject to amortization but is evaluated annually as of October 1 for impairment or more frequently if impairment indicators are present that would indicate it is more likely than not that the fair value of the reporting unit is less than its carrying amount. As part of the evaluation, we compare our estimate of the fair value of the reporting unit with its carrying value, including goodwill. If the carrying value of the reporting unit exceeds its fair value, a computation of the implied fair value of the goodwill is compared with its related carrying value. If the carrying value of the reporting unit goodwill exceeds the implied fair value of that goodwill, an impairment loss is recognized in the amount of the excess. Judgments and assumptions are inherent in our management’s estimates of fair value.
Other intangibles assets [Policy Text Block]	Other intangible assets Our identifiable intangible assets are primarily related to gas gathering, processing, and fractionation contractual customer relationships. Our intangible assets are amortized on a straight-line basis over the period in which these assets contribute to our cash flows. We evaluate these assets for changes in the expected remaining useful lives and would reflect any changes prospectively through amortization over the revised remaining useful life.
Impairment of property, plant, and equipment, other identifiable intangible assets, and investments [Policy Text Block]	Impairment of property, plant, and equipment, other identifiable intangible assets, and investments We evaluate our property, plant, and equipment and other identifiable intangible assets for impairment when events or changes in circumstances indicate, in our management’s judgment, that the carrying value of such assets may not be recoverable. When an indicator of impairment has occurred, we compare our management’s estimate of undiscounted future cash flows attributable to the assets to the carrying value of the assets to determine whether an impairment has occurred and we may apply a probability-weighted approach to consider the likelihood of different cash flow assumptions and possible outcomes including selling in the near term or holding for the remaining estimated useful life. If an impairment of the carrying value has occurred, we determine the amount of the impairment recognized in the financial statements by estimating the fair value of the assets and recording a loss for the amount that the carrying value exceeds the estimated fair value. This evaluation is performed at the lowest level for which separately identifiable cash flows exist. For assets identified to be disposed of in the future and considered held for sale, we compare the carrying value to the estimated fair value less the cost to sell to determine if recognition of an impairment is required. Until the assets are disposed of, the estimated fair value, which includes estimated cash flows from operations until the assumed date of sale, is recalculated when related events or circumstances change. We evaluate our investments for impairment when events or changes in circumstances indicate, in our management’s judgment, that the carrying value of such investments may have experienced an other-than-temporary decline in value. When evidence of loss in value has occurred, we compare our estimate of fair value of the investment to the carrying value of the investment to determine whether an impairment has occurred. If the estimated fair value is less than the carrying value and we consider the decline in value to be other-than-temporary, the excess of the carrying value over the fair value is recognized in the consolidated financial statements as an impairment charge. Judgments and assumptions are inherent in our management’s estimate of undiscounted future cash flows and an asset’s or investment’s fair value. Additionally, judgment is used to determine the probability of sale with respect to assets considered for disposal.
Contingent liabilities [Policy Text Block]	Contingent liabilities We record liabilities for estimated loss contingencies, including environmental matters, when we assess that a loss is probable and the amount of the loss can be reasonably estimated. These liabilities are calculated based upon our assumptions and estimates with respect to the likelihood or amount of loss and upon advice of legal counsel, engineers, or other third parties regarding the probable outcomes of the matters. These calculations are made without consideration of any potential recovery from third parties. We recognize insurance recoveries or reimbursements from others when realizable. Revisions to these liabilities are generally reflected in income when new or different facts or information become known or circumstances change that affect the previous assumptions or estimates.
Cash flows from revolving credit facilities and commercial paper program [Policy Text Block]	Cash flows from revolving credit facilities and commercial paper program Proceeds and payments related to borrowings under our credit facilities are reflected in the financing activities in the Consolidated Statement of Cash Flows on a gross basis. Proceeds and payments related to borrowings under our commercial paper program are reflected in the financing activities in the Consolidated Statement of Cash Flows on a net basis, as the outstanding notes generally have maturity dates less than three months from the date of issuance. (See Note 14 – Debt, Banking Arrangements, and Leases .)
Treasury stock [Policy Text Block]	Treasury stock Treasury stock purchases are accounted for under the cost method whereby the entire cost of the acquired stock is recorded as Treasury stock in the Consolidated Balance Sheet . Gains and losses on the subsequent reissuance of shares are credited or charged to Capital in excess of par value in the Consolidated Balance Sheet using the average-cost method.
Derivative instruments and hedging activities [Policy Text Block]	Derivative instruments and hedging activities We may utilize derivatives to manage a portion of our commodity price risk. These instruments consist primarily of swaps, futures, and forward contracts involving short- and long-term purchases and sales of physical energy commodities. We report the fair value of derivatives, except those for which the normal purchases and normal sales exception has been elected, in Other current assets and deferred charges ; Regulatory assets, deferred charges, and other ; Accrued liabilities ; or Other noncurrent liabilities in the Consolidated Balance Sheet . We determine the current and noncurrent classification based on the timing of expected future cash flows of individual trades. We report these amounts on a gross basis. Additionally, we report cash collateral receivables and payables with our counterparties on a gross basis. (See Note 17 – Fair Value Measurements, Guarantees, and Concentration of Credit Risk .) The accounting for the changes in fair value of a commodity derivative can be summarized as follows: Derivative Treatment Accounting Method Normal purchases and normal sales exception Accrual accounting Designated in a qualifying hedging relationship Hedge accounting All other derivatives Mark-to-market accounting We may elect the normal purchases and normal sales exception for certain short- and long-term purchases and sales of physical energy commodities. Under accrual accounting, any change in the fair value of these derivatives is not reflected on the balance sheet after the initial election of the exception. We may also designate a hedging relationship for certain commodity derivatives. For a derivative to qualify for designation in a hedging relationship, it must meet specific criteria and we must maintain appropriate documentation. We establish hedging relationships pursuant to our risk management policies. We evaluate the hedging relationships at the inception of the hedge and on an ongoing basis to determine whether the hedging relationship is, and is expected to remain, highly effective in achieving offsetting changes in fair value or cash flows attributable to the underlying risk being hedged. We also regularly assess whether the hedged forecasted transaction is probable of occurring. If a derivative ceases to be or is no longer expected to be highly effective, or if we believe the likelihood of occurrence of the hedged forecasted transaction is no longer probable, hedge accounting is discontinued prospectively, and future changes in the fair value of the derivative are recognized currently in Product sales or Product costs in the Consolidated Statement of Operations . For commodity derivatives designated as a cash flow hedge, the effective portion of the change in fair value of the derivative is reported in Accumulated other comprehensive income (loss) (AOCI) in the Consolidated Balance Sheet and reclassified into earnings in the period in which the hedged item affects earnings. Any ineffective portion of the derivative’s change in fair value is recognized currently in Product sales or Product costs in the Consolidated Statement of Operations . Gains or losses deferred in AOCI associated with terminated derivatives, derivatives that cease to be highly effective hedges, derivatives for which the forecasted transaction is reasonably possible but no longer probable of occurring, and cash flow hedges that have been otherwise discontinued remain in AOCI until the hedged item affects earnings. If it becomes probable that the forecasted transaction designated as the hedged item in a cash flow hedge will not occur, any gain or loss deferred in AOCI is recognized in Product sales or Product costs in the Consolidated Statement of Operations at that time. The change in likelihood of a forecasted transaction is a judgmental decision that includes qualitative assessments made by management. For commodity derivatives that are not designated in a hedging relationship, and for which we have not elected the normal purchases and normal sales exception, we report changes in fair value currently in Product sales or Product costs in the Consolidated Statement of Operations . Certain gains and losses on derivative instruments included in the Consolidated Statement of Operations are netted together to a single net gain or loss, while other gains and losses are reported on a gross basis. Gains and losses recorded on a net basis include unrealized gains and losses on all derivatives that are not designated as hedges and for which we have not elected the normal purchases and normal sales exception. Realized gains and losses on derivatives that require physical delivery, as well as natural gas derivatives for NGL processing activities and which are not held for trading purposes nor were entered into as a pre-contemplated buy/sell arrangement, are recorded on a gross basis.
Revenue recognition [Policy Text Block]	Revenue recognition Revenues As a result of the ratemaking process, certain revenues collected by us may be subject to refunds upon the issuance of final orders by the FERC in pending rate proceedings. We record estimates of rate refund liabilities considering our and other third-party regulatory proceedings, advice of counsel, and other risks. Service revenues Revenues from our gas pipeline businesses include services pursuant to long-term firm transportation and storage agreements. These agreements provide for a reservation charge based on the volume of contracted capacity and a commodity charge based on the volume of gas delivered, both at rates specified in our FERC tariffs. We recognize revenues for reservation charges ratably over the contract period regardless of the volume of natural gas that is transported or stored. Revenues for commodity charges, from both firm and interruptible transportation services and storage injection and withdrawal services, are recognized when natural gas is delivered at the agreed upon delivery point or when natural gas is injected or withdrawn from the storage facility. Certain revenues from our midstream operations include those derived from natural gas gathering, processing, treating, and compression services and are performed under volumetric-based fee contracts. These revenues are recorded when services have been performed. Certain of our gas gathering agreements have minimum volume commitments. If a customer under such an agreement fails to meet its minimum volume commitment for a specified period, generally measured on an annual basis, it is obligated to pay a contractually determined fee based upon the shortfall between actual production volumes and the minimum volume commitment for that period. The revenue associated with minimum volume commitments is recognized in the period that the actual shortfall is determined and is no longer subject to future reduction or offset. Crude oil gathering and transportation revenues and offshore production handling fees are recognized when the services have been performed. Certain offshore production handling contracts contain fixed payment terms that result in the deferral of revenues until such services have been performed or such capacity has been made available. Storage revenues from our midstream operations associated with prepaid contracted storage capacity contracts are recognized on a straight-line basis over the life of the contract as services are provided. Product sales In the course of providing transportation services to customers of our interstate natural gas pipeline businesses, we may receive different quantities of gas from shippers than the quantities delivered on behalf of those shippers. The resulting imbalances are primarily settled through the purchase and sale of gas with our customers under terms provided for in our FERC tariffs. Revenue is recognized from the sale of gas upon settlement of the transportation and exchange imbalances. We market NGLs, crude oil, natural gas, and olefins that we purchase from our producer customers as part of the overall service provided to producers. Revenues from marketing NGLs are recognized when the products have been sold and delivered. Under our keep-whole and percent-of-liquids processing contracts, we retain the rights to all or a portion of the NGLs extracted from the producers’ natural gas stream and recognize revenues when the extracted NGLs are sold and delivered. Our domestic olefins business produces olefins from purchased or produced feedstock and we recognize revenues when the olefins are sold and delivered. Our Canadian business has processing and fractionation operations where we retain certain NGLs and olefins from an upgrader’s offgas stream and we recognize revenues when the fractionated products are sold and delivered.
Interest capitalized [Policy Text Block]	Interest capitalized We capitalize interest during construction on major projects with construction periods of at least 3 months and a total project cost in excess of $1 million . Interest is capitalized on borrowed funds and, where regulation by the FERC exists, on internally generated funds (equity AFUDC). The latter is included in Other income (expense) – net below Operating income (loss) in the Consolidated Statement of Operations . The rates used by regulated companies are calculated in accordance with FERC rules. Rates used by nonregulated companies are based on our average interest rate on debt.
Employee stock-based awards [Policy Text Block]	Employee stock-based awards We recognize compensation expense on employee stock-based awards, net of estimated forfeitures, on a straight-line basis. (See Note 16 – Equity-Based Compensation .)
Pension and other postretirement benefits [Policy Text Block]	Pension and other postretirement benefits The funded status of each of the pension and other postretirement benefit plans is recognized separately in the Consolidated Balance Sheet as either an asset or liability. The funded status is the difference between the fair value of plan assets and the plan’s benefit obligation. The plans’ benefit obligations and net periodic benefit costs are actuarially determined and impacted by various assumptions and estimates. (See Note 9 – Employee Benefit Plans .) The discount rates are determined separately for each of our pension and other postretirement benefit plans based on an approach specific to our plans. The year-end discount rates are determined considering a yield curve comprised of high-quality corporate bonds and the timing of the expected benefit cash flows of each plan. The expected long-term rates of return on plan assets are determined by combining a review of the historical returns within the portfolio, the investment strategy included in the plans’ investment policy statement, and capital market projections for the asset classes in which the portfolio is invested, as well as the weighting of each asset class. Unrecognized actuarial gains and losses and unrecognized prior service costs and credits are deferred and recorded in AOCI or, for Transco and Northwest Pipeline, as a regulatory asset or liability, until amortized as a component of net periodic benefit cost. Unrecognized actuarial gains and losses in excess of 10 percent of the greater of the benefit obligation or the market-related value of plan assets are amortized over the participants’ average remaining future years of service, which is approximately 12 years for our pension plans and approximately 7 years for our other postretirement benefit plans. Unrecognized prior service costs and credits for the other postretirement benefit plans are amortized on a straight line basis over the average remaining years of service to eligibility for eligible plan participants, which is approximately 4 years . The expected return on plan assets component of net periodic benefit cost is calculated using the market-related value of plan assets. For our pension plans, the market-related value of plan assets is equal to the fair value of plan assets adjusted to reflect the amortization of gains or losses associated with the difference between the expected and actual return on plan assets over a 5 -year period. Additionally, the market-related value of assets may be no more than 110 percent or less than 90 percent of the fair value of plan assets at the beginning of the year. The market-related value of plan assets for our other postretirement benefit plans is equal to the unadjusted fair value of plan assets at the beginning of the year. In May 2015, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2015-07 “Fair Value Measurement (Topic 820): Disclosures for Investments in Certain Entities That Calculate Net Asset Value per Share (or Its Equivalent)” (ASU 2015-07). ASU 2015-07 removes from the fair value hierarchy investments measured using the net asset value per share (or its equivalent) practical expedient. The standard primarily impacts the presentation of certain investments included in our employee benefit plans. The standard is effective for financial statements issued for interim and annual reporting periods beginning after December 15, 2015, and requires retrospective presentation. Early adoption is permitted. Management elected to early adopt the provisions of this new standard. As a result, the plan asset investments measured at fair value using the net asset value per share (or its equivalent) practical expedient have been excluded from the presentation of plan assets within the fair value hierarchy. This standard has been applied retrospectively to the presentation of prior periods, as required upon adoption. (See Note 9 – Employee Benefit Plans .)
Income taxes [Policy Text Block]	Income taxes We include the operations of our domestic corporate subsidiaries and income from our subsidiary partnerships in our consolidated federal income tax return and also file tax returns in various foreign and state jurisdictions as required. Deferred income taxes are computed using the liability method and are provided on all temporary differences between the financial basis and the tax basis of our assets and liabilities. Our management’s judgment and income tax assumptions are used to determine the levels, if any, of valuation allowances associated with deferred tax assets.
Earnings (loss) per common share [Policy Text Block]	Earnings (loss) per common share Basic earnings (loss) per common share in the Consolidated Statement of Operations is based on the sum of the weighted-average number of common shares outstanding and vested restricted stock units. Diluted earnings (loss) per common share in the Consolidated Statement of Operations includes any dilutive effect of stock options, nonvested restricted stock units, and convertible debt, unless otherwise noted. Diluted earnings (loss) per common share are calculated using the treasury-stock method.
Foreign currency translation [Policy Text Block]	Foreign currency translation Certain of our foreign subsidiaries use the Canadian dollar as their functional currency. Assets and liabilities of such foreign subsidiaries are translated at the spot rate in effect at the applicable reporting date, and the combined statements of operations are translated into the U.S. dollar at the average exchange rates in effect during the applicable period. The resulting cumulative translation adjustment is recorded as a separate component of AOCI in the Consolidated Balance Sheet . Transactions denominated in currencies other than the functional currency are recorded based on exchange rates at the time such transactions arise. Subsequent changes in exchange rates when the transactions are settled result in transaction gains and losses which are reflected in Other (income) expense – net in the Consolidated Statement of Operations .

General, Description of Busin31

General, Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Regulatory Assets and Liabilities [Table Text Block]	Our current and noncurrent regulatory asset and liability balances for the years ended December 31, 2015 and 2014 are as follows: December 31, 2015 2014 (Millions) Current assets reported within Other current assets and deferred charges $ 84 $ 81 Noncurrent assets reported within Regulatory assets, deferred charges, and other 370 337 Total regulated assets $ 454 $ 418 Current liabilities reported within Accrued liabilities $ 4 $ 11 Noncurrent liabilities reported within Other noncurrent liabilities 434 375 Total regulated liabilities $ 438 $ 386

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2015
Business Acquisition [Line Items]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The following table presents the allocation of the acquisition-date fair value of the major classes of the assets acquired, which are presented in the Williams Partners segment, liabilities assumed, and noncontrolling interest at July 1, 2014. The fair value of accounts receivable acquired equaled contractual amounts receivable. Changes to the preliminary allocation disclosed in Exhibit 99.1 of our Form 8-K dated May 6, 2015, which were recorded in the first quarter of 2015, reflect an increase of $150 million in Property, plant, and equipment and $25 million in Goodwill , and a decrease of $168 million in Other intangible assets and $7 million in Investments . These adjustments during the measurement period were not considered significant to require retrospective revisions of our financial statements. (Millions) Accounts receivable $ 168 Other current assets 63 Investments 5,865 Property, plant, and equipment 7,165 Goodwill 499 Other intangible assets 8,841 Current liabilities (408 ) Debt (4,052 ) Other noncurrent liabilities (9 ) Noncontrolling interest in ACMP’s subsidiaries (958 ) Noncontrolling interest in ACMP (6,544 )
Business Acquisition, Pro Forma Information [Table Text Block]	The following unaudited pro forma Revenues and Net income attributable to The Williams Companies, Inc. for the years ended December 31, 2014 and 2013, are presented as if the ACMP Acquisition had been completed on January 1, 2013. These pro forma amounts are not necessarily indicative of what the actual results would have been if the acquisition had in fact occurred on the date or for the periods indicated, nor do they purport to project Revenues or Net income attributable to The Williams Companies, Inc. for any future periods or as of any date. These amounts do not give effect to any potential cost savings, operating synergies, or revenue enhancements to result from the transactions or the potential costs to achieve these cost savings, operating synergies, and revenue enhancements. December 31, 2014 2013 (Millions) Revenues $ 8,181 $ 7,906 Net income attributable to The Williams Companies, Inc. $ 622 $ 356

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2015
Variable Interest Entity Disclosures [Abstract]
Schedule of Variable Interest Entities [Table Text Block]	The following table presents amounts included in our Consolidated Balance Sheet that are for the use or obligation of our consolidated VIEs. December 31, 2015 2014 Classification (Millions) Assets (liabilities): Cash and cash equivalents $ 70 $ 113 Cash and cash equivalents Accounts receivable 71 52 Accounts and notes receivable – net, Trade and other Other current assets 2 3 Other current assets and deferred charges Property, plant, and equipment – net 3,000 2,794 Property, plant, and equipment – net Goodwill 47 103 Goodwill Other intangible assets – net 1,436 1,493 Other intangible assets – net of accumulated amortization Other noncurrent assets — 14 Regulatory assets, deferred charges, and other Accounts payable (59 ) (48 ) Accounts payable Accrued liabilities (14 ) (36 ) Accrued liabilities Current deferred revenue (62 ) (45 ) Accrued liabilities Noncurrent deferred income taxes — (13 ) Deferred income tax liabilities Asset retirement obligation (93 ) (94 ) Other noncurrent liabilities Noncurrent deferred revenue associated with customer advance payments (331 ) (395 ) Other noncurrent liabilities

Investing Activities (Tables)

Investing Activities (Tables)	12 Months Ended
	Dec. 31, 2015
Investments [Abstract]
Investments [Table Text Block]	December 31, 2015 2014 (Millions) Equity-method investments: Appalachia Midstream Investments (1) $ 2,464 $ 3,033 UEOM — 62% (2) 1,525 1,411 Delaware basin gas gathering system — 50% 977 1,478 Discovery — 60% 602 602 OPPL – 50% 445 453 Caiman II — 58% 418 432 Laurel Mountain — 69% 391 459 Gulfstream — 50% 293 317 Other 221 215 $ 7,336 $ 8,400 ___________ (1) Includes equity-method investments in multiple gathering systems in the Marcellus Shale with an approximate average 45 percent interest. (2) WPZ acquired an approximate 13 percent additional interest in UEOM in 2015. (See Note 2 – Acquisitions ).
Contributions [Table Text Block]	Purchases of and contributions to equity-method investments in the Consolidated Statement of Cash Flows We generally fund our portion of significant expansion or development projects of these investees through additional capital contributions. These transactions increased the carrying value of our investments and included: Years Ended December 31, 2015 2014 2013 (Millions) UEOM (1) $ 357 $ 57 $ — Appalachia Midstream Investments 93 84 — Delaware basin gas gathering system 57 20 — Discovery 35 106 193 Caiman II — 175 192 Other 53 40 70 $ 595 $ 482 $ 455 ___________ (1) 2015 includes additional interest in UEOM acquired by WPZ. (See Note 2 – Acquisitions .)
Dividends and distributions [Table Text Block]	Dividends and distributions The organizational documents of entities in which we have an equity-method interest generally require distribution of available cash to members on at least a quarterly basis. These transactions reduced the carrying value of our investments and included: Years Ended December 31, 2015 2014 2013 (Millions) Appalachia Midstream Investments $ 219 $ 130 $ — Discovery 116 36 12 Gulfstream 88 81 81 OPPL 45 27 27 UEOM 42 — — Caiman II 33 13 — Delaware basin gas gathering system 33 — — Laurel Mountain 31 39 — Access Midstream Investments — 64 93 Other 26 50 34 $ 633 $ 440 $ 247
Summarized Financial Position and Results of Operations of Equity Method Investments [Table Text Block]	Summarized Financial Position and Results of Operations of All Equity-Method Investments December 31, 2015 2014 (Millions) Assets (liabilities): Current assets $ 773 $ 599 Noncurrent assets 9,549 9,135 Current liabilities (633 ) (850 ) Noncurrent liabilities (1,450 ) (954 ) Years Ended December 31, 2015 2014 2013 (Millions) Gross revenue $ 1,707 $ 1,623 $ 2,406 Operating income 690 534 699 Net income 611 460 627

Other Income and Expenses (Tabl

Other Income and Expenses (Tables)	12 Months Ended
	Dec. 31, 2015
Other Income and Expenses [Abstract]
Other Income and Expense [Table Text Block]	The following table presents certain gains or losses reflected in Other (income) expense – net within Costs and expenses in our Consolidated Statement of Operations : Years Ended December 31, 2015 2014 2013 (Millions) Williams Partners Impairment of certain assets (See Note 17) $ 145 $ 52 $ — Amortization of regulatory assets associated with asset retirement obligations 33 33 30 Contingency gain settlement (1) — (154 ) — Net gain related to partial acreage dedication release — (12 ) — Loss related to sale of certain assets — 10 — Write-off of the Eminence abandonment regulatory asset not recoverable through rates — (3 ) 12 Insurance recoveries associated with the Eminence abandonment — — (16 ) Loss associated with a producer claim — — 25 Williams NGL & Petchem Services Impairment of certain assets (See Note 17) 64 — 20 ________________ (1) In November 2014, we settled a claim arising from the resolution of a contingent gain related to claims associated with the purchase of a business in a prior period. Pursuant to the settlement, we received $154 million in cash, all of which was recognized as a gain in the fourth quarter of 2014.

Provision (Benefit) for Incom36

Provision (Benefit) for Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Schedule of Components of Provision (benefit) for income taxes [Table Text Block]	The Provision (benefit) for income taxes includes: Years Ended December 31, 2015 2014 2013 (Millions) Current: Federal $ — $ (9 ) $ (17 ) State (7 ) 2 7 Foreign (55 ) 10 (13 ) (62 ) 3 (23 ) Deferred: Federal (317 ) 1,108 348 State (25 ) 119 40 Foreign 5 19 36 (337 ) 1,246 424 Provision (benefit) for income taxes $ (399 ) $ 1,249 $ 401
Provision for income taxes at federal statutory rate [Table Text Block]	Reconciliations from the Provision (benefit) at statutory rate to recorded Provision (benefit) for income taxes are as follows: Years Ended December 31, 2015 2014 2013 (Millions) Provision (benefit) at statutory rate $ (600 ) $ 1,255 $ 378 Increases (decreases) in taxes resulting from: Impact of nontaxable noncontrolling interests 263 (75 ) (78 ) State income taxes (net of federal benefit) (21 ) 82 26 Foreign operations – net 8 (11 ) (32 ) Taxes on undistributed earnings of foreign subsidiaries – net — (37 ) 99 Translation adjustment of certain unrecognized tax benefits (71 ) — — Other – net 22 35 8 Provision (benefit) for income taxes $ (399 ) $ 1,249 $ 401
Deferred tax liabilities and Deferred tax assets [Table Text Block]	Significant components of Deferred income tax liabilities and Deferred income tax assets are as follows: December 31, 2015 2014 (Millions) Deferred income tax liabilities: Property, plant, and equipment $ 4 $ 4 Investments 5,272 5,472 Other 15 10 Total deferred income tax liabilities 5,291 5,486 Deferred income tax assets: Accrued liabilities 150 178 Minimum tax credits 139 137 Foreign tax credit 193 251 Federal loss carryovers 485 134 State losses and credits 296 250 Other 42 97 Total deferred income tax assets 1,305 1,047 Less valuation allowance 190 206 Net deferred income tax assets 1,115 841 Overall net deferred income tax liabilities $ 4,176 $ 4,645
Reconciliation of unrecognized tax benefits [Table Bext Block]	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows: 2015 2014 (Millions) Balance at beginning of period $ 89 $ 66 Additions based on tax positions related to the current year — 11 Additions for tax positions of prior years 2 12 Reductions for tax positions of prior years — — Settlement with taxing authorities — — Changes due to currency translation (36 ) — Balance at end of period $ 55 $ 89

Earnings (Loss) Per Common Sh37

Earnings (Loss) Per Common Share from Continuing Operations (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Earnings (loss) per common share from continuing operations [Table Text Block]	Years Ended December 31, 2015 2014 2013 (Dollars in millions, except per-share amounts; shares in thousands) Income (loss) from continuing operations attributable to The Williams Companies, Inc. available to common stockholders for basic and diluted earnings (loss) per common share $ (571 ) $ 2,110 $ 441 Basic weighted-average shares 749,271 719,325 682,948 Effect of dilutive securities: Nonvested restricted stock units — 2,234 1,995 Stock options — 2,064 2,149 Convertible debentures — 18 93 Diluted weighted-average shares (1) 749,271 723,641 687,185 Earnings (loss) per common share from continuing operations: Basic $ (.76 ) $ 2.93 $ 0.65 Diluted $ (.76 ) $ 2.91 $ 0.64 (1) For the year ended December 31, 2015, 1.7 million weighted-average nonvested restricted stock units and 1.5 million weighted-average stock options have been excluded from the computation of diluted earnings (loss) per common share as their inclusion would be antidilutive due to our loss from continuing operations attributable to The Williams Companies, Inc.

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Changes in benefit obligations and plan assets [Table Text Block]	The following table presents the changes in benefit obligations and plan assets for pension benefits and other postretirement benefits for the years indicated. Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 (Millions) Change in benefit obligation: Benefit obligation at beginning of year $ 1,544 $ 1,384 $ 233 $ 213 Service cost 59 40 2 2 Interest cost 58 62 9 10 Plan participants’ contributions — — 2 2 Benefits paid (101 ) (86 ) (13 ) (14 ) Plan amendment — — — 1 Actuarial loss (gain) (91 ) 144 (31 ) 21 Settlements (5 ) (3 ) — (1 ) Curtailments — — — (1 ) Other — 3 — — Benefit obligation at end of year 1,464 1,544 202 233 Change in plan assets: Fair value of plan assets at beginning of year 1,293 1,241 208 201 Actual return on plan assets (11 ) 78 (1 ) 13 Employer contributions 65 63 5 6 Plan participants’ contributions — — 2 2 Benefits paid (101 ) (86 ) (13 ) (14 ) Settlements (5 ) (3 ) — — Fair value of plan assets at end of year 1,241 1,293 201 208 Funded status — underfunded $ (223 ) $ (251 ) $ (1 ) $ (25 ) Accumulated benefit obligation $ 1,432 $ 1,516
Underfunded status of our pension plans and other postretirement benefit plans [Table Text Block]	The underfunded status of our pension plans and other postretirement benefit plans presented in the previous table are recognized in the Consolidated Balance Sheet within the following accounts: December 31, 2015 2014 (Millions) Underfunded pension plans: Current liabilities $ (2 ) $ (2 ) Noncurrent liabilities (221 ) (249 ) Underfunded other postretirement benefit plans: Current liabilities (7 ) (7 ) Noncurrent assets (liabilities) 6 (18 )
Pre-tax amounts not yet recognized in net periodic benefit cost [Table Text Block]	Pre-tax amounts not yet recognized in Net periodic benefit cost at December 31 are as follows: Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 (Millions) Amounts included in Accumulated other comprehensive income (loss) : Prior service credit $ — $ — $ 11 $ 17 Net actuarial loss (544 ) (593 ) (18 ) (28 ) Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline: Prior service credit N/A N/A $ 19 $ 30 Net actuarial gain (loss) N/A N/A 6 (4 )
Schedule of Net Benefit Costs [Table Text Block]	Net periodic benefit cost for the years ended December 31 consist of the following: Pension Benefits Other Postretirement Benefits 2015 2014 2013 2015 2014 2013 (Millions) Components of net periodic benefit cost: Service cost $ 59 $ 40 $ 44 $ 2 $ 2 $ 2 Interest cost 58 62 51 9 10 11 Expected return on plan assets (75 ) (76 ) (61 ) (12 ) (12 ) (9 ) Amortization of prior service cost (credit) — — 1 (17 ) (20 ) (12 ) Amortization of net actuarial loss 42 39 60 2 — 4 Net actuarial (gain) loss from settlements and curtailments 2 1 — — (1 ) — Reclassification to regulatory liability — — — 3 4 2 Net periodic benefit cost $ 86 $ 66 $ 95 $ (13 ) $ (17 ) $ (2 )
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss) [Table Text Block]	Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss) before taxes for the years ended December 31 consist of the following: Pension Benefits Other Postretirement Benefits 2015 2014 2013 2015 2014 2013 (Millions) Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss) : Net actuarial gain (loss) $ 5 $ (142 ) $ 277 $ 8 $ (18 ) $ 23 Prior service (cost) credit — — — — (1 ) 23 Amortization of prior service cost (credit) — — 1 (6 ) (8 ) (4 ) Amortization of net actuarial loss 42 39 60 2 — 1 Loss from settlements and curtailments 2 1 — — 1 — Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss) $ 49 $ (102 ) $ 338 $ 4 $ (26 ) $ 43
Schedule of Regulatory Assets / Liabilities [Table Text Block]	Other changes in plan assets and benefit obligations for our other postretirement benefit plans associated with Transco and Northwest Pipeline are recognized in regulatory assets/liabilities. Amounts recognized in regulatory assets/ liabilities for the years ended December 31 consist of the following: 2015 2014 2013 (Millions) Other changes in plan assets and benefit obligations recognized in regulatory (assets) liabilities: Net actuarial gain (loss) $ 10 $ (2 ) $ 62 Prior service credit — — 36 Amortization of prior service credit (11 ) (12 ) (8 ) Amortization of net actuarial loss — — 3
Pre-tax amounts expected to be amortized in net periodic benefit cost [Table Text Block]	Pre-tax amounts expected to be amortized in Net periodic benefit cost in 2016 are as follows: Pension Benefits Other Postretirement Benefits (Millions) Amounts included in Accumulated other comprehensive income (loss) : Prior service credit $ — $ (6 ) Net actuarial loss 31 — Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline: Prior service credit N/A $ (9 ) Net actuarial loss N/A —
Schedule of Assumptions Used [Table Text Block]	The weighted-average assumptions utilized to determine benefit obligations as of December 31 are as follows: Pension Benefits Other Postretirement Benefits 2015 2014 2015 2014 Discount rate 4.38 % 3.96 % 4.50 % 4.12 % Rate of compensation increase 4.88 4.62 N/A N/A The weighted-average assumptions utilized to determine Net periodic benefit cost for the years ended December 31 are as follows: Pension Benefits Other Postretirement Benefits 2015 2014 2013 2015 2014 2013 Discount rate 3.96 % 4.68 % 3.43 % 4.12 % 4.80 % 3.97 % Expected long-term rate of return on plan assets 6.38 6.85 5.90 5.70 6.11 5.26 Rate of compensation increase 4.62 4.56 4.57 N/A N/A N/A
One percentage point change in assumed health care cost trend rates effects [Table Text Block]	A one-percentage-point change in assumed health care cost trend rates would have the following effects: Point increase Point decrease (Millions) Effect on total of service and interest cost components $ — $ — Effect on other postretirement benefit obligation 7 (6 )
Fair values of plan assets [Table Text Block]	The fair values of our pension plan assets at December 31, 2015 and 2014 by asset class are as follows: 2015 Quoted Prices Significant Significant Total (Millions) Pension assets: Cash management fund $ 8 $ — $ — $ 8 Equity securities: U.S. large cap 83 — — 83 U.S. small cap 64 — — 64 Fixed income securities (1): U.S. Treasury securities 65 — — 65 Government and municipal bonds — 8 — 8 Mortgage and asset-backed securities — 87 — 87 Corporate bonds — 145 — 145 Insurance company investment contracts and other — 5 — 5 $ 220 $ 245 $ — 465 Commingled investment funds measured at net asset value practical expedient (3): Equities — U.S. large cap 367 Equities — International small cap 27 Equities — International emerging markets 50 Equities — International developed markets 153 Fixed income — U.S. long duration 95 Fixed income — Corporate bonds 84 Total assets at fair value at December 31, 2015 $ 1,241 2014 Quoted Prices Significant Significant Total (Millions) Pension assets: Cash management fund $ 25 $ — $ — $ 25 Equity securities: U.S. large cap 221 — — 221 U.S. small cap 139 — — 139 International developed markets large cap growth — 60 — 60 Fixed income securities (1): U.S. Treasury securities 31 — — 31 Mortgage-backed securities — 65 — 65 Corporate bonds — 222 — 222 Insurance company investment contracts and other — 7 — 7 $ 416 $ 354 $ — 770 Commingled investment funds measured at net asset value practical expedient (3): Equities — U.S. large cap 189 Equities — International small cap 24 Equities — Emerging markets value 27 Equities — Emerging markets growth 19 Equities — International developed markets large cap value 101 Fixed income — Corporate bonds 163 Total assets at fair value at December 31, 2014 $ 1,293 The fair values of our other postretirement benefits plan assets at December 31, 2015 and 2014 by asset class are as follows: 2015 Quoted Prices Significant Significant Total (Millions) Other postretirement benefit assets: Cash management funds $ 11 $ — $ — $ 11 Equity securities: U.S. large cap 37 — — 37 U.S. small cap 20 — — 20 International developed markets large cap growth 1 9 — 10 Emerging markets growth — 1 — 1 Fixed income securities (2): U.S. Treasury securities 7 — — 7 Government and municipal bonds — 12 — 12 Mortgage and asset-backed securities — 9 — 9 Corporate bonds — 15 — 15 $ 76 $ 46 $ — 122 Commingled investment funds measured at net asset value practical expedient (3): Equities — U.S. large cap 37 Equities — International small cap 3 Equities — International emerging markets 5 Equities — International developed markets 16 Fixed income — U.S. long duration 10 Fixed income — Corporate bonds 8 Total assets at fair value at December 31, 2015 $ 201 2014 Quoted Prices Significant Significant Total (Millions) Other postretirement benefit assets: Cash management funds $ 13 $ — $ — $ 13 Equity securities: U.S. large cap 53 — — 53 U.S. small cap 28 — — 28 International developed markets large cap growth — 15 — 15 Emerging markets growth 1 2 — 3 Fixed income securities (2): U.S. Treasury securities 3 — — 3 Government and municipal bonds — 11 — 11 Mortgage-backed securities — 7 — 7 Corporate bonds — 23 — 23 $ 98 $ 58 $ — 156 Commingled investment funds measured at net asset value practical expedient (3): Equities — U.S. large cap 19 Equities — International small cap 2 Equities — Emerging markets value 3 Equities — Emerging markets growth 2 Equities — International developed markets large cap value 10 Fixed income — Corporate bonds 16 Total assets at fair value at December 31, 2014 $ 208 ____________ (1) The weighted-average credit quality rating of the pension assets fixed income security portfolio is investment grade with a weighted-average duration of approximately 8 years for 2015 and 6 years for 2014 . (2) The weighted-average credit quality rating of the other postretirement benefit assets fixed income security portfolio is investment grade with a weighted-average duration of approximately 7 years for 2015 and 5 years for 2014 . (3) In accordance with our adoption of ASU 2015-07, investments measured at fair value using the net asset value per share (or its equivalent) practical expedient have not been classified within the fair value hierarchy. (See Note 1 – General, Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies .) The stated intents of the funds vary based on each commingled fund’s investment objective. These objectives generally include strategies to replicate or outperform various market indices. Certain standard withdrawal restrictions generally apply, which may include redemption notification period restrictions ranging from 10 to 30 days. Additionally, the fund managers retain the right to restrict withdrawals from and/or purchases into the funds so as not to disadvantage other investors in the funds. Generally, the funds also reserve the right to make all or a portion of the redemption in-kind rather than in cash or a combination of cash and in-kind.
Expected benefit payments [Table Text Block]	Following are the expected benefits to be paid by the plans. These estimates are based on the same assumptions previously discussed and reflect future service as appropriate. The actuarial assumptions are based on long-term expectations and include, but are not limited to, assumptions as to average expected retirement age and form of benefit payment. Actual benefit payments could differ significantly from expected benefit payments if near-term participant behaviors differ significantly from the actuarial assumptions. Pension Benefits Other Postretirement Benefits (Millions) 2016 $ 95 $ 13 2017 102 13 2018 105 13 2019 106 13 2020 110 14 2021-2025 578 66

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2015
Inventory, Net [Abstract]
Inventories [Table Text Block]	December 31, 2015 2014 (Millions) Natural gas liquids, olefins, and natural gas in underground storage $ 57 $ 150 Materials, supplies, and other 70 81 $ 127 $ 231

Property, Plant, and Equipment

Property, Plant, and Equipment (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property, Plant, and Equipment [Table Text Block]	The following table presents nonregulated and regulated Property, plant, and equipment – net as presented on the Consolidated Balance Sheet for the years ended: Estimated Useful Life (1) (Years) Depreciation Rates (1) (%) December 31, 2015 2014 (Millions) Nonregulated: Natural gas gathering and processing facilities 5 - 40 $ 20,789 $ 18,749 Construction in progress Not applicable 1,366 2,648 Other 2 - 45 2,170 1,850 Regulated: Natural gas transmission facilities 1.20 - 6.97 12,189 10,867 Construction in progress Not applicable Not applicable 941 985 Other 5 - 45 1.35 - 33.33 1,584 1,336 Total property, plant, and equipment, at cost 39,039 36,435 Accumulated depreciation and amortization (9,460 ) (8,354 ) Property, plant, and equipment — net $ 29,579 $ 28,081 __________ (1) Estimated useful life and depreciation rates are presented as of December 31, 2015 . Depreciation rates and estimated useful lives for regulated assets are prescribed by the FERC.
Asset Retirement Obligation [Table Text Block]	The following table presents the significant changes to our ARO, of which $858 million and $791 million are included in Other noncurrent liabilities with the remaining current portion in Accrued liabilities at December 31, 2015 and 2014 , respectively. December 31, 2015 2014 (Millions) Beginning balance $ 831 $ 561 Liabilities incurred 42 101 Liabilities settled (1) (3 ) (21 ) Accretion expense 60 44 Revisions (2) (15 ) 146 Ending balance $ 915 $ 831 ___________ (1) For 2014, liabilities settled include $7 million related to the abandonment of certain of Transco’s natural gas storage caverns that are associated with a leak in 2010. (2) Several factors are considered in the annual review process, including inflation rates, current estimates for removal cost, discount rates, and the estimated remaining useful life of the assets. The 2015 revisions reflect changes in removal cost estimates and the estimated remaining useful life of assets, a decrease in the inflation rate, and increases in the discount rates used in the annual review process. The 2014 revisions primarily reflect an increase in the estimated retirement costs for our offshore pipelines, an increase in the inflation rate, and decreases in the discount rates used in the annual review process.

Goodwill and Other Intangible41

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill [Table Text Block]	Changes in the carrying amount of goodwill by reportable segment for the periods indicated are as follows: Williams Partners (Millions) December 31, 2014 $ 1,120 Purchase accounting adjustment 25 Impairment (1,098 ) December 31, 2015 $ 47
Schedule of Finite-Lived Intangible Assets [Table Text Block]	The gross carrying amount and accumulated amortization of Other intangible assets – net of accumulated amortization at December 31 are as follows: 2015 2014 Gross Carrying Amount Accumulated Amortization Gross Carrying Amount Accumulated Amortization (Millions) Contractual customer relationships $ 10,633 $ (663 ) $ 10,763 $ (310 )

Accrued Liabilities (Tables)

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2015
Accrued Liabilities, Current [Abstract]
Accrued Liabilities [Table Text Block]	December 31, 2015 2014 (Millions) Interest on debt $ 284 $ 268 Employee costs 215 167 Special distribution repayable to Gulfstream (See Note 5 - Investing Activities) 149 — Deferred income 94 82 Asset retirement obligations 57 40 Other, including other loss contingencies 279 343 $ 1,078 $ 900

Debt, Banking Arrangements, a43

Debt, Banking Arrangements, and Leases (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table Text Block]	Long-Term Debt December 31, 2015 2014 (Millions) Unsecured: Transco: 6.4% Notes due 2016 (2) $ 200 $ 200 6.05% Notes due 2018 250 250 7.08% Debentures due 2026 8 8 7.25% Debentures due 2026 200 200 5.4% Notes due 2041 375 375 4.45% Notes due 2042 400 400 Northwest Pipeline: 7% Notes due 2016 175 175 5.95% Notes due 2017 185 185 6.05% Notes due 2018 250 250 7.125% Debentures due 2025 85 85 WPZ: 3.8% Notes due 2015 (1) — 750 7.25% Notes due 2017 600 600 5.25% Notes due 2020 1,500 1,500 4.125% Notes due 2020 600 600 4% Notes due 2021 500 500 5.875% Notes due 2021 — 750 3.6% Notes due 2022 1,250 — 3.35% Notes due 2022 750 750 6.125% Notes due 2022 750 750 4.5% Notes due 2023 600 600 4.875% Notes due 2023 1,400 1,400 4.3% Notes due 2024 1,000 1,000 4.875% Notes due 2024 750 750 3.9% Notes due 2025 750 750 4.0% Notes due 2025 750 — December 31, 2015 2014 (Millions) 6.3% Notes due 2040 $ 1,250 $ 1,250 5.8% Notes due 2043 400 400 5.4% Notes due 2044 500 500 4.9% Notes due 2045 500 500 5.1% Notes due 2045 1,000 — Term Loan, variable interest rate, due 2018 850 — Credit facility loans 1,310 640 WMB: 7.875% Notes due 2021 371 371 3.7% Notes due 2023 850 850 4.55% Notes due 2024 1,250 1,250 7.5% Debentures due 2031 339 339 7.75% Notes due 2031 252 252 8.75% Notes due 2032 445 445 5.75% Notes due 2044 650 650 Various — 5.5% to 10.25% Notes and Debentures due 2019 to 2033 55 55 Credit facility loans 650 370 Capital lease obligations 1 5 Debt issuance costs (123 ) (108 ) Net unamortized debt premium (discount) 110 187 Total long-term debt, including current portion 23,988 20,784 Long-term debt due within one year (176 ) (4 ) Long-term debt $ 23,812 $ 20,780 ___________ (1) Presented as long-term debt at December 31, 2014, due to WPZ's intent and ability to refinance. (2) Presented as long-term debt at December 31, 2015, due to Transco’s intent and ability to refinance.
Schedule of Maturities of Long-term Debt [Table Text Block]	The following table presents aggregate minimum maturities of long-term debt, excluding net unamortized debt premium (discount), debt issuance costs, and capital lease obligations, for each of the next five years: December 31, 2015 (Millions) 2016 $ 175 2017 785 2018 1,350 2019 32 2020 2,121
Schedule of Line of Credit Facilities [Table Text Block]	Credit Facilities December 31, 2015 Available Outstanding (Millions) WMB Long-term credit facility $ 1,500 $ 650 Letters of credit under certain bilateral bank agreements 14 WPZ Long-term credit facility (1) 3,500 1,310 Letters of credit under certain bilateral bank agreements 2 Short-term credit facility 150 — ________________ (1) In managing our available liquidity, we do not expect a maximum outstanding amount in excess of the capacity of our credit facility inclusive of any outstanding amounts under our commercial paper program.
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	The future minimum annual rentals under noncancelable operating leases, are payable as follows: December 31, 2015 (Millions) 2016 $ 86 2017 74 2018 56 2019 45 2020 39 Thereafter 119 Total $ 419

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table presents the changes in AOCI by component, net of income taxes: Cash Flow Hedges Foreign Currency Translation Pension and Other Post Retirement Benefits Total (Millions) Balance at December 31, 2014 $ (1 ) $ 31 $ (371 ) $ (341 ) Other comprehensive income (loss) before reclassifications 3 (134 ) 8 (123 ) Amounts reclassified from accumulated other comprehensive income (loss) (3 ) — 25 22 Other comprehensive income (loss) — (134 ) 33 (101 ) Balance at December 31, 2015 $ (1 ) $ (103 ) $ (338 ) $ (442 )
Reclassifications Out Of Accumulated Other Comprehensive Income [Table Text Block]	Reclassifications out of AOCI are presented in the following table by component for the year ended December 31, 2015 : Component Reclassifications Classification (Millions) Cash flow hedges: Energy commodity contracts $ (3 ) Product sales Total cash flow hedges, before income taxes (3 ) Pension and other postretirement benefits: Amortization of prior service cost (credit) included in net periodic benefit cost (6 ) Note 9 – Employee Benefit Plans Amortization of actuarial (gain) loss included in net periodic benefit cost 46 Note 9 – Employee Benefit Plans Total pension and other postretirement benefits, before income taxes 40 Reclassifications before income taxes 37 Income tax benefit (15 ) Provision (benefit) for income taxes Reclassifications during the period $ 22

Equity-Based Compensation (Tabl

Equity-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2015
Williams Companies Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Option Rollfoward and related information [Table Text Block]	The following summary reflects stock option activity and related information for the year ended December 31, 2015 : Stock Options Options Weighted- Average Exercise Price Aggregate Intrinsic Value (Millions) (Millions) Outstanding at December 31, 2014 5.8 $ 25.86 Granted 1.0 $ 49.15 Exercised (1.1 ) $ 19.30 Outstanding at December 31, 2015 5.7 $ 31.51 $ 15 Exercisable at December 31, 2015 4.0 $ 25.52 $ 15
Schedule of Cash Proceeds Received from Share-based Payment Awards [Table Text Block]	The following table summarizes additional information related to stock option activity during each of the last three years: Years Ended December 31, 2015 2014 2013 (Millions) Total intrinsic value of options exercised $ 37 $ 48 $ 23 Tax benefits realized on options exercised $ 13 $ 18 $ 9 Cash received from the exercise of options $ 20 $ 31 $ 13
Stock Options Schedule of Valuation Assumptions [Table Text Block]	The estimated fair value at date of grant of options for our common stock granted in each respective year, using the Black-Scholes option pricing model, is as follows: 2015 2014 2013 Weighted-average grant date fair value of options for our common stock granted during the year, per share $ 7.61 $ 7.50 $ 5.94 Weighted-average assumptions: Dividend yield 4.8 % 4.2 % 4.3 % Volatility 27.8 % 28.0 % 29.7 % Risk-free interest rate 1.8 % 2.2 % 1.4 % Expected life (years) 6.0 6.5 6.5
Nonvested Restricted Stock Unit Rollforward and related information [Table Text Block]	The following summary reflects nonvested restricted stock unit activity and related information for the year ended December 31, 2015 . Restricted Stock Units Outstanding Shares Weighted- Average Fair Value (1) (Millions) Nonvested at December 31, 2014 3.6 $ 33.90 Granted 1.4 $ 40.15 Forfeited (0.1 ) $ 36.49 Vested (1.5 ) $ 27.45 Nonvested at December 31, 2015 3.4 $ 39.38 ______________ (1) Performance-based restricted stock units are valued utilizing a Monte Carlo valuation method using measures of total shareholder return. Certain of the performance-based restricted stock units are subject to a holding period of up to two years after the vesting date. Discounts for the restrictions of liquidity were applied to the estimated fair value at the date of the awards and ranged from 5.83 percent to 15.58 percent . The discounts were developed using the Chaffe model and the Finnerty model. All other restricted stock units are valued at the grant-date market price. Restricted stock units generally vest after three years .
Other restricted stock unit information [Table Text Block]	Value of Restricted Stock Units 2015 2014 2013 Weighted-average grant date fair value of restricted stock units granted during the year, per share $ 40.15 $ 42.79 $ 30.43 Total fair value of restricted stock units vested during the year ($’s in millions) $ 42 $ 27 $ 27
Williams Partners Long Term Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested Restricted Stock Unit Rollforward and related information [Table Text Block]	The following summary reflects nonvested WPZ restricted common unit activity and related information for the year ended December 31, 2015 : Restricted Common Units Outstanding Units Weighted- Average Fair Value (Millions) Nonvested at December 31, 2014 1.3 $ 59.35 Adjustment for unit split in ACMP Merger 0.1 $ — Forfeited (0.1 ) $ 58.05 Vested (0.1 ) $ 59.28 Nonvested at December 31, 2015 1.2 $ 55.93

Fair Value Measurements, Guar46

Fair Value Measurements, Guarantees, and Concentration of Credit Risk (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Assets and Liabilities Measured On Recurring Basis [Table Text Block]	The following table presents, by level within the fair value hierarchy, certain of our financial assets and liabilities. The carrying values of cash and cash equivalents, accounts receivable, commercial paper, and accounts payable approximate fair value because of the short-term nature of these instruments. Therefore, these assets and liabilities are not presented in the following table. Fair Value Measurements Using Carrying Amount Fair Value Quoted Prices In Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (Millions) Assets (liabilities) at December 31, 2015: Measured on a recurring basis: ARO Trust investments $ 67 $ 67 $ 67 $ — $ — Energy derivatives assets not designated as hedging instruments 5 5 — 3 2 Energy derivatives liabilities not designated as hedging instruments (2 ) (2 ) — — (2 ) Additional disclosures: Notes receivable and other 12 30 10 2 18 Long-term debt, including current portion (1) (23,987 ) (19,606 ) — (19,606 ) — Guarantee (29 ) (16 ) — (16 ) — Assets (liabilities) at December 31, 2014: Measured on a recurring basis: ARO Trust investments $ 48 $ 48 $ 48 $ — $ — Energy derivatives assets not designated as hedging instruments 3 3 1 — 2 Energy derivatives liabilities not designated as hedging instruments (2 ) (2 ) — — (2 ) Additional disclosures: Notes receivable and other 30 57 — 4 53 Long-term debt, including current portion (1) (20,779 ) (21,131 ) — (21,131 ) — Guarantee (31 ) (27 ) — (27 ) — ___________ (1) Excludes capital leases. The carrying value has been reduced by $123 million and $108 million of debt acquisition costs at December 31, 2015 and 2014, respectively. (See Note 14 – Debt, Banking Arrangements, and Leases .)
Concentration of receivables, net of allowances, by product or service [Table Text Block]	The following table summarizes concentration of receivables, net of allowances. December 31, 2015 2014 (Millions) NGLs, natural gas, and related products and services $ 823 $ 730 Transportation of natural gas and related products 202 175 Income tax receivable 7 167 Other 9 67 Total $ 1,041 $ 1,139
Property, Plant and Equipment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurements, Nonrecurring [Table Text Block]	Impairments Years Ended December 31, Date of Measurement Fair Value 2015 2014 (Millions) Impairment of certain assets (1) June 30, 2014 $ 46 $ 17 Impairment of certain assets (1) December 31, 2014 32 13 Impairment of certain assets (1) June 30, 2015 17 $ 20 Impairment of certain assets (2) December 31, 2014 1 12 Impairment of certain assets (3) December 31, 2015 13 94 Impairment of certain assets (4) December 31, 2015 40 64 Level 3 fair value measurements of certain assets 178 42 Other impairments (5) 31 10 Total impairments of certain assets $ 209 $ 52 ______________ (1) Reflects impairment charges for our Williams Partners segment associated with certain surplus equipment. Certain of these assets were previously presented as held for sale, but are now considered held for use and reported in Property, plant, and equipment – net in the Consolidated Balance Sheet at December 31, 2015. The estimated fair value was determined by a market approach based on our analysis of observable inputs in the principal market. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations . (2) Reflects impairment charges for our Williams Partners segment associated with certain surplus equipment considered held for sale and reported in Other current assets and deferred charges in the Consolidated Balance Sheet . The estimated fair value was determined by a market approach based on our analysis of observable inputs in the principal market. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations . (3) Reflects an impairment charge within our Williams Partners segment associated with previously capitalized project development costs for a gas processing plant, the completion of which is now considered remote due to unfavorable impact of low natural gas prices on customer drilling activities. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations .The assessed fair value primarily represents the estimated salvage value of certain equipment measured using a market approach based on our analysis of observable inputs in the principal market and is reported in Property, plant, and equipment – net in the Consolidated Balance Sheet. (4) Reflects an impairment charge within our Williams NGL & Petchem Services segment associated with previously capitalized project development costs for an olefins pipeline project, the completion of which is now considered remote due to the lack of customer interest. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations . The assessed fair value primarily represents the estimated value of unused pipeline measured using a market approach based on our analysis of observable inputs in the principal market and is reported in Property, plant, and equipment – net in the Consolidated Balance Sheet. (5) Reflects multiple individually insignificant impairments of other certain assets that may no longer be in use or are surplus in nature for which the fair value was determined to be zero or an insignificant salvage value. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations
Investments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurements, Nonrecurring [Table Text Block]	Date of Measurement Fair Value Impairments (Millions) Impairments of equity-method investments (1) September 30, 2015 $ 1,203 $ 461 Impairments of equity-method investments (2) December 31, 2015 4,017 890 Other impairment of equity-method investment December 31, 2015 58 8 Level 3 fair value measurements of equity-method investments $ 1,359 ______________ (1) Reflects other-than-temporary impairment charges related to Williams Partners’ equity-method investments in the Delaware basin gas gathering system and certain of the Appalachia Midstream Investments reflected within Impairment of equity-method investments in the Consolidated Statement of Operations . The historical carrying value of these investments was initially recorded based on estimated fair value during the third quarter of 2014 in conjunction with the ACMP Acquisition. We estimated the fair value of these investments using an income approach based on expected future cash flows and appropriate discount rates. The determination of estimated future cash flows involved significant assumptions regarding gathering volumes and related capital spending. Discount rates utilized were 11.8 percent and 8.8 percent for the Delaware basin gas gathering system and certain of the Appalachia Midstream Investments, respectively, and reflected our cost of capital as impacted by market conditions, and risks associated with the underlying businesses. (2) Reflects other-than-temporary impairment charges related to Williams Partners’ equity-method investments in the Delaware basin gas gathering system, certain of the Appalachia Midstream Investments, UEOM, and Laurel Mountain, reflected within Impairment of equity-method investments in the Consolidated Statement of Operations . We estimated the fair value of these investments using an income approach based on expected future cash flows and appropriate discount rates. The determination of estimated future cash flows involved significant assumptions regarding gathering volumes and related capital spending. Discount rates utilized ranged from 10.8 percent to 14.4 percent and reflected further fourth quarter increases in our cost of capital, revised estimates of expected future cash flows, and risks associated with the underlying businesses.

Segment Disclosures (Tables)

Segment Disclosures (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]	The following geographic area data includes Revenues from external customers based on product shipment origin and Long-lived assets based upon physical location. United States Canada Total (Millions) Revenues from external customers: 2015 $ 7,247 $ 113 $ 7,360 2014 7,229 408 7,637 2013 6,703 157 6,860 Long-lived assets: 2015 $ 38,016 $ 1,580 $ 39,596 2014 38,290 1,364 39,654 2013 19,260 1,240 20,500
Reconciliation of segment revenues [Table Text Block]	The following table reflects the reconciliation of Segment revenues to Total revenues as reported in the Consolidated Statement of Operations and Other financial information . Williams Partners Williams NGL & Petchem Services (1) Other Eliminations Total (Millions) 2015 Segment revenues: Service revenues External $ 5,134 $ 2 $ 28 $ — $ 5,164 Internal 1 — 158 (159 ) — Total service revenues 5,135 2 186 (159 ) 5,164 Product sales External 2,196 — — — 2,196 Internal — — — — — Total product sales 2,196 — — — 2,196 Total revenues $ 7,331 $ 2 $ 186 $ (159 ) $ 7,360 Other financial information: Additions to long-lived assets $ 2,960 $ 360 $ 28 $ (12 ) $ 3,336 Proportional Modified EBITDA of equity-method investments 699 — — 699 2014 Segment revenues: Service revenues External $ 3,887 $ — $ 229 $ — $ 4,116 Internal 1 — 30 (31 ) — Total service revenues 3,888 — 259 (31 ) 4,116 Product sales External 3,521 — — — 3,521 Internal — — — — — Total product sales 3,521 — — — 3,521 Total revenues $ 7,409 $ — $ 259 $ (31 ) $ 7,637 Other financial information: Additions to long-lived assets (2) $ 20,413 $ 291 $ 54 $ (2 ) $ 20,756 Proportional Modified EBITDA of equity-method investments 431 (78 ) 85 438 2013 Segment revenues: Service revenues External $ 2,914 $ — $ 25 $ — $ 2,939 Internal — — 11 (11 ) — Total service revenues 2,914 — 36 (11 ) 2,939 Product sales External 3,921 — — — 3,921 Internal — — — — — Total product sales 3,921 — — — 3,921 Total revenues $ 6,835 $ — $ 36 $ (11 ) $ 6,860 Other financial information: Additions to long-lived assets $ 3,409 $ 295 $ 27 $ — $ 3,731 Proportional Modified EBITDA of equity-method investments 209 — 197 406 __________ (1) Includes certain projects under development and thus nominal reported revenues to date. (2) 2014 Additions to long-lived assets within our Williams Partners segment primarily includes the acquisition-date fair value of long-lived assets from the ACMP Acquisition. (See Note 2 - Acquisitions.)
Reconciliation of Modified EBITDA from Segments to Consolidated [Table Text Block]	The following table reflects the reconciliation of Modified EBITDA to Net income (loss) as reported in the Consolidated Statement of Operations . Years Ended December 31, 2015 2014 2013 (Millions) Modified EBITDA by segment: Williams Partners $ 4,003 $ 3,244 $ 2,447 Williams NGL & Petchem Services (83 ) (115 ) (33 ) Other (29 ) 103 197 3,891 3,232 2,611 Accretion expense associated with asset retirement obligations for nonregulated operations (28 ) (18 ) (15 ) Depreciation and amortization expenses (1,738 ) (1,176 ) (815 ) Impairment of goodwill (1,098 ) — — Equity earnings (losses) 335 144 134 Gain on remeasurement of equity-method investment — 2,544 — Impairment of equity-method investments (1,359 ) — — Other investing income (loss) – net 27 43 81 Proportional Modified EBITDA of equity-method investments (699 ) (438 ) (406 ) Interest expense (1,044 ) (747 ) (510 ) (Provision) benefit for income taxes 399 (1,249 ) (401 ) Income (loss) from discontinued operations, net of tax — 4 (11 ) Net income (loss) $ (1,314 ) $ 2,339 $ 668
Total assets and equity method investments by reporting segment [Table Text Block]	The following table reflects Total assets and Equity-method investments by reportable segments: Total Assets Equity-Method Investments December 31, 2015 December 31, 2014 December 31, 2015 December 31, 2014 (Millions) Williams Partners $ 47,870 $ 49,248 $ 7,336 $ 8,399 Williams NGL & Petchem Services 835 612 — — Other 850 1,186 — 1 Eliminations (535 ) (591 ) — — Total $ 49,020 $ 50,455 $ 7,336 $ 8,400

Schedule I Condensed Financia48

Schedule I Condensed Financial Information of Registrant (Tables)	12 Months Ended
	Dec. 31, 2015
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Income Statement [Table Text Block]	The Williams Companies, Inc. Schedule I — Condensed Financial Information of Registrant Statement of Comprehensive Income (Loss) (Parent) Years Ended December 31, 2015 2014 2013 (Millions, except per-share amounts) Equity in earnings of consolidated subsidiaries $ 232 $ 1,799 $ 1,564 Equity earnings (losses) from investment in Access Midstream Partners — (7 ) 30 Interest incurred — external (255 ) (206 ) (156 ) Interest incurred — affiliate (828 ) (797 ) (722 ) Interest income — affiliate 6 10 71 Gain on remeasurement of equity-method investment — 2,544 — Other income (expense) — net (75 ) (13 ) 32 Income (loss) from continuing operations before income taxes (920 ) 3,330 819 Provision (benefit) for income taxes (349 ) 1,220 378 Income (loss) from continuing operations (571 ) 2,110 441 Income (loss) from discontinued operations — 4 (11 ) Net income (loss) $ (571 ) $ 2,114 $ 430 Basic earnings (loss) per common share: Income (loss) from continuing operations $ (.76 ) $ 2.93 $ .65 Income (loss) from discontinued operations — .01 (.02 ) Net income (loss) $ (.76 ) $ 2.94 $ .63 Weighted-average shares (thousands) 749,271 719,325 682,948 Diluted earnings (loss) per common share: Income (loss) from continuing operations $ (.76 ) $ 2.91 $ .64 Income (loss) from discontinued operations — .01 (.02 ) Net income (loss) $ (.76 ) $ 2.92 $ .62 Weighted-average shares (thousands) 749,271 723,641 687,185 Other comprehensive income (loss): Equity in other comprehensive income (loss) of consolidated subsidiaries $ (204 ) $ (96 ) $ (41 ) Other comprehensive income (loss) attributable to The Williams Companies, Inc. 33 (80 ) 239 Other comprehensive income (loss) (171 ) (176 ) 198 Less: Other comprehensive income (loss) attributable to noncontrolling interests (70 ) (19 ) — Comprehensive income (loss) attributable to The Williams Companies, Inc. $ (672 ) $ 1,957 $ 628 See accompanying notes.
Condensed Balance Sheet [Table Text Block]	The Williams Companies, Inc. Schedule I — Condensed Financial Information of Registrant – (Continued) Balance Sheet (Parent) December 31, 2015 2014 (Millions) ASSETS Current assets: Cash and cash equivalents $ 12 $ 49 Other current assets and deferred charges 62 246 Total current assets 74 295 Investments in and advances to consolidated subsidiaries 30,927 31,405 Property, plant, and equipment — net 99 99 Other noncurrent assets 12 12 Total assets $ 31,112 $ 31,811 LIABILITIES AND STOCKHOLDERS’ EQUITY Current liabilities: Accounts payable $ 27 $ 27 Other current liabilities 163 174 Total current liabilities 190 201 Long-term debt 4,811 4,528 Notes payable — affiliates 15,506 13,295 Pension, other postretirement, and other noncurrent liabilities 336 409 Deferred income tax liabilities 4,121 4,601 Contingent liabilities and commitments Equity: Common stock 784 782 Other stockholders’ equity 5,364 7,995 Total stockholders’ equity 6,148 8,777 Total liabilities and stockholders’ equity $ 31,112 $ 31,811 See accompanying notes.
Condensed Cash Flow Statement [Table Text Block]	The Williams Companies, Inc. Schedule I — Condensed Financial Information of Registrant – (Continued) Statement of Cash Flows (Parent) Years Ended December 31, 2015 2014 2013 (Millions) NET CASH FLOWS PROVIDED (USED) BY OPERATING ACTIVITIES $ (1,209 ) $ (500 ) $ 19 FINANCING ACTIVITIES: Proceeds from long-term debt 2,097 2,935 — Payments of long-term debt (1,817 ) (671 ) (1 ) Changes in notes payable to affiliates 2,211 2,465 1,892 Tax benefit of stock-based awards — 25 19 Proceeds from issuance of common stock 27 3,416 18 Dividends paid (1,836 ) (1,412 ) (982 ) Other — net (2 ) (17 ) (3 ) Net cash provided (used) by financing activities 680 6,741 943 INVESTING ACTIVITIES: Capital expenditures (29 ) (54 ) (23 ) Purchase of Access Midstream Partners — (5,995 ) — Changes in investments in and advances to consolidated subsidiaries 521 (450 ) (985 ) Other — net — 25 (12 ) Net cash provided (used) by investing activities 492 (6,474 ) (1,020 ) Increase (decrease) in cash and cash equivalents (37 ) (233 ) (58 ) Cash and cash equivalents at beginning of year 49 282 340 Cash and cash equivalents at end of year $ 12 $ 49 $ 282 See accompanying notes.

General, Description of Busin49

General, Description of Business and Basis of Presentation (Details) $ / shares in Units, $ in Millions

Sep. 28, 2015USD ($)$ / shares

Feb. 02, 2015

Feb. 26, 2016USD ($)

Nov. 30, 2015USD ($)

Jun. 30, 2015USD ($)

Oct. 31, 2014USD ($)

Feb. 28, 2014USD ($)shares

Dec. 31, 2015shares

Jun. 30, 2014USD ($)

Dec. 31, 2015

Dec. 31, 2015USD ($)$ / shares

Dec. 31, 2014USD ($)$ / shares

Dec. 31, 2013USD ($)$ / shares

Dec. 20, 2012

General and Description Of Business [Abstract]

Common Stock, Dividends, Per Share, Declared | $ / shares

$ 2.45

$ 1.9575

$ 1.4375

Basis Of Presentation [Abstract]

Master limited partnership, general partner ownership percentage

2.00%

Changes in ownership of consolidated subsidiaries, net

$ 94

$ 44

$ (243)

ETC Merger [Member]

General and Description Of Business [Abstract]

Common Stock, Dividends, Per Share, Declared | $ / shares

$ 0.10

WPZ Merger Agreement [Member]

General and Description Of Business [Abstract]

Termination Fee

$ 428

Maximum Reduction Of Quarterly Incentive Distributions

$ 209

Basis Of Presentation [Abstract]

Reduction in incentive distribution rights payment

$ 209

WPZ Merger Agreement [Member] | Subsequent Event [Member]

Basis Of Presentation [Abstract]

Reduction in incentive distribution rights payment

$ 209

Canada Dropdown [Member]

Basis Of Presentation [Abstract]

Proceeds from Divestiture of Businesses

$ 56

$ 31

Number Of Limited Partner Units Received1 | shares

25,577,521

Payments for Previous Acquisition

$ 56

Reduction in incentive distribution rights payment

$ 2

Noncontrolling Interest [Member]

Basis Of Presentation [Abstract]

Changes in ownership of consolidated subsidiaries, net

254

137

(652)

Capital in excess of par value [Member]

Basis Of Presentation [Abstract]

Changes in ownership of consolidated subsidiaries, net

(160)

$ (73)

$ 409

Deferred Income Taxes [Member]

Basis Of Presentation [Abstract]

Income Tax Effects Allocated Directly to Equity, Other

$ (94)

Gulfstream Natural Gas System, L.L.C.[Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

50.00%

50.00%

50.00%

Utica East Ohio Midstream, LLC [Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

62.00%

62.00%

62.00%

Delaware Basin Gas Gathering System [Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

50.00%

50.00%

50.00%

Laurel Mountain Midstream, LLC [Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

69.00%

69.00%

69.00%

Discovery Producer Services LLC [Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

60.00%

60.00%

60.00%

Overland Pass Pipeline Company LLC [Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

50.00%

50.00%

50.00%

Energy Transfer Corp L P [Member]

General and Description Of Business [Abstract]

Master limited partnership ownership percentage

19.00%

Williams Partners L.P. [Member]

Basis Of Presentation [Abstract]

Master limited partnership, general partner ownership percentage

2.00%

Williams Partners L.P. [Member] | Access Midstream Partners Acquisition [Member] | Publicly Held WPZ Common Units into ACMP Common Units [Member]

General and Description Of Business [Abstract]

Conversion Ratio

0.86672

Williams Partners L.P. [Member] | Access Midstream Partners Acquisition [Member] | Privately Held WPZ Units Into ACMP Common Units [Member]

General and Description Of Business [Abstract]

Conversion Ratio

0.80036

Williams Partners L.P. [Member] | Access Midstream Partners Acquisition [Member] | ACMP Units Into Merged Partnership Units [Member]

General and Description Of Business [Abstract]

Conversion Ratio

1.06152

Williams Partners L.P. [Member] | Access Midstream Partners Acquisition [Member] | Class D WPZ Units Into WPZ Common Units [Member]

General and Description Of Business [Abstract]

Conversion Ratio

1

Williams Partners L.P. [Member] | Private Placement [Member]

Basis Of Presentation [Abstract]

Sale Of Stock Number Of Shares Issued In Transaction | shares

1,790,840

Williams Partners L.P. [Member] | General and Limited Partner [Member]

General and Description Of Business [Abstract]

Master limited partnership ownership percentage

60.00%

Williams Partners L.P. [Member] | General and Limited Partner [Member] | Access Midstream Partners Acquisition [Member]

General and Description Of Business [Abstract]

Master limited partnership ownership percentage

60.00%

Williams Partners [Member]

General and Description Of Business [Abstract]

Number Of Interstate Natural Gas Pipelines

2

Williams Partners [Member] | Gulfstream Natural Gas System, L.L.C.[Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

50.00%

50.00%

50.00%

Williams Partners [Member] | Utica East Ohio Midstream, LLC [Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

62.00%

62.00%

62.00%

Basis Of Presentation [Abstract]

Reduction in incentive distribution rights payment

$ 2

Williams Partners [Member] | Delaware Basin Gas Gathering System [Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

50.00%

50.00%

50.00%

Williams Partners [Member] | Laurel Mountain Midstream, LLC [Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

69.00%

69.00%

69.00%

Williams Partners [Member] | Caiman Energy II [Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

58.00%

58.00%

58.00%

Williams Partners [Member] | Discovery Producer Services LLC [Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

60.00%

60.00%

60.00%

Williams Partners [Member] | Overland Pass Pipeline Company LLC [Member]

General and Description Of Business [Abstract]

Equity Method Investment, Ownership Percentage

50.00%

50.00%

50.00%

Williams Partners [Member] | Appalachia Midstream Services, LLC [Member]

General and Description Of Business [Abstract]

Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest

45.00%

Williams Partners [Member] | Constitution Pipeline Company LLC [Member]

General and Description Of Business [Abstract]

Variable Interest Entity Ownership Percentage

41.00%

Stock Consideration [Member] | ETC Merger [Member]

General and Description Of Business [Abstract]

Conversion Ratio

1.8716

Cash Consideration [Member] | ETC Merger [Member]

General and Description Of Business [Abstract]

Business Acquisition, Share Price | $ / shares

$ 43.50

Mixed Consideration [Member] | ETC Merger [Member]

General and Description Of Business [Abstract]

Conversion Ratio

1.5274

Business Acquisition, Share Price | $ / shares

$ 8

Summary of Significant Accounti

Summary of Significant Accounting Policies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Regulatory Assets and Liabilities Disclosure [Abstract]
Regulatory Assets, Current	$ 84	$ 81
Regulatory Assets, Noncurrent	370	337
Total regulatory assets	454	418
Regulatory Liabilities, Current	4	11
Regulatory Liabilities, Noncurrent	434	375
Total regulatory liabilities	$ 438	$ 386
Interest Capitalized [Abstract]
Minimum period of construction for capitalization of interest	3 months
Minimum total project cost for capitalization of interest	$ 1
General Discussion of Pension and Other Postretirement Benefits [Abstract]
Threshold For Amortization Of Unrecognized Actuarial Gains Losses	10.00%
Pension Benefits [Member]
General Discussion of Pension and Other Postretirement Benefits [Abstract]
Approximate Amortization Period Of Net Actuarial Gain Loss	12 years
Amortization Period Of Difference Between Expected And Actual Return On Plan Assets	5 years
Other Postretirement Benefits [Member]
General Discussion of Pension and Other Postretirement Benefits [Abstract]
Approximate Amortization Period Of Net Actuarial Gain Loss	7 years
Amortization Period Of Unrecognized Prior Service Costs Credits	4 years
Maximum [Member] | Pension Benefits [Member]
General Discussion of Pension and Other Postretirement Benefits [Abstract]
Threshold For Market Related Value	110.00%
Minimum [Member] | Pension Benefits [Member]
General Discussion of Pension and Other Postretirement Benefits [Abstract]
Threshold For Market Related Value	90.00%

Acquisitions (Details)

Acquisitions (Details) $ in Millions

1 Months Ended

3 Months Ended

6 Months Ended

12 Months Ended

Jun. 30, 2015USD ($)

May. 31, 2015USD ($)

Sep. 30, 2015USD ($)

Mar. 31, 2015USD ($)

Jul. 02, 2014USD ($)

Dec. 31, 2015USD ($)

Dec. 31, 2014USD ($)

Dec. 31, 2013USD ($)

Dec. 20, 2012USD ($)

Jul. 01, 2014USD ($)

Jun. 30, 2013

Equity Method Investments and Joint Ventures [Abstract]

Payments to Acquire Equity Method Investments

$ 595

$ 482

$ 455

Business Combination, Consideration Transferred [Abstract]

Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest

2.00%

Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain

0

2,544

0

Business Acquisition, Purchase Price Allocation [Abstract]

Goodwill

47

1,120

Business Acquisition, Pro Forma Information [Abstract]

Gain on remeasurement of equity-method investment

0

2,544

$ 0

Williams Partners [Member]

Business Acquisition, Purchase Price Allocation [Abstract]

Goodwill

$ 47

1,120

Access Midstream [Member]

Equity Method Investments and Joint Ventures [Abstract]

Equity Method Investment, Ownership Percentage

23.00%

24.00%

Payments to Acquire Equity Method Investments

$ 2,190

Business Combination, Consideration Transferred [Abstract]

Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value

$ 4,600

Utica East Ohio Midstream, LLC [Member]

Equity Method Investments and Joint Ventures [Abstract]

Equity Method Investment, Ownership Percentage

62.00%

Payments to Acquire Equity Method Investments

[1]

$ 357

57

$ 0

Utica East Ohio Midstream, LLC [Member] | Williams Partners [Member]

Equity Method Investments and Joint Ventures [Abstract]

Equity Method Investment, Ownership Percentage

62.00%

Payments to Acquire Equity Method Investments

$ 357

Reduction in incentive distribution rights payment

$ 2

Access Midstream Partners Acquisition [Member]

Business Acquisition [Line Items]

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment

$ 150

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles

(168)

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Goodwill

25

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Investments

$ (7)

Business Combination, Consideration Transferred [Abstract]

Payments to Acquire Businesses, Gross

$ 5,995

Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain

2,544

Acquired Finite-lived Intangible Assets, Weighted Average Useful Life

30 years

Percentage Of Finite Lived Intangible Assets Impacted By Our Intent Or Ability To Renew Or Extend Arrangement

56.00%

Acquired Finite-lived Intangible Asset, Weighted-Average Period before Renewal or Extension

17 years

Business Acquisition, Pro Forma Information [Abstract]

Business Acquisition, Pro Forma Revenue

8,181

7,906

Business Acquisition, Pro Forma Net Income (Loss)

622

$ 356

Gain on remeasurement of equity-method investment

2,544

Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual

781

Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual

165

Access Midstream Partners Acquisition [Member] | Selling, General and Administrative Expenses [Member]

Business Combination, Consideration Transferred [Abstract]

Business Combination, Acquisition Related Costs

16

Access Midstream Partners Acquisition [Member] | Interest Incurred [Member]

Business Combination, Consideration Transferred [Abstract]

Business Combination, Acquisition Related Costs

9

Access Midstream Partners Acquisition [Member] | Income Loss From Equity Method Investment [Member]

Business Combination, Consideration Transferred [Abstract]

Business Combination, Integration Related Costs

$ 19

Access Midstream Partners Acquisition [Member] | Pro Forma [Member]

Business Combination, Consideration Transferred [Abstract]

Acquired Finite-lived Intangible Assets, Weighted Average Useful Life

30 years

Access Midstream Partners Acquisition [Member] | Williams Partners [Member]

Business Acquisition, Purchase Price Allocation [Abstract]

Accounts receivable

$ 168

Other current assets

63

Investments

5,865

Property, plant, and equipment

7,165

Goodwill

499

Other intangible assets

8,841

Current liabilities

(408)

Debt

(4,052)

Other noncurrent liabilities

$ (9)

Access Midstream Partners Acquisition [Member] | Access Midstream Partners L.P. [Member]

Business Combination, Consideration Transferred [Abstract]

Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage

26.00%

Access Midstream Partners Acquisition [Member] | Access Midstream Partners L.P. [Member] | Williams Partners [Member]

Business Acquisition, Purchase Price Allocation [Abstract]

Noncontrolling interest

$ (6,544)

Access Midstream Partners Acquisition [Member] | ACMP's subsidiaries [Member] | Williams Partners [Member]

Business Acquisition, Purchase Price Allocation [Abstract]

Noncontrolling interest

$ (958)

Eagle Ford Gathering System [Member]

Business Combination, Consideration Transferred [Abstract]

Acquired Finite-lived Intangible Assets, Weighted Average Useful Life

30 years

Acquired Finite-lived Intangible Asset, Weighted-Average Period before Renewal or Extension

10 years

Business Acquisition, Purchase Price Allocation [Abstract]

Other intangible assets

$ 32

Eagle Ford Gathering System [Member] | Williams Partners [Member]

Business Acquisition [Line Items]

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment

$ 20

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles

$ (20)

Number Of Miles Of Pipeline Acquired

140

Business Combination, Consideration Transferred [Abstract]

Payments to Acquire Businesses, Gross

$ 112

Business Acquisition, Purchase Price Allocation [Abstract]

Property, plant, and equipment

$ 80

General Partner [Member] | Access Midstream [Member]

Equity Method Investments and Joint Ventures [Abstract]

Equity Method Investment, Ownership Percentage

50.00%

General Partner [Member] | Access Midstream Partners Acquisition [Member]

Business Combination, Consideration Transferred [Abstract]

Business Acquisition, Percentage of Voting Interests Acquired

50.00%

Limited Partner [Member] | Access Midstream Partners L.P. [Member]

Equity Method Investments and Joint Ventures [Abstract]

Equity Method Investment, Ownership Percentage

24.00%

Additional Investment [Member] | Utica East Ohio Midstream, LLC [Member]

Equity Method Investments and Joint Ventures [Abstract]

Equity Method Investment, Ownership Percentage

13.00%

[1]

2015 includes additional interest in UEOM acquired by WPZ. (See Note 2 – Acquisitions.)

Variable Interest Entities (Det

Variable Interest Entities (Details) - Variable Interest Entity, Primary Beneficiary [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Cash and cash equivalents [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$ 70	$ 113
Accounts receivable [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	71	52
Other current assets [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	2	3
Property, plant, and equipment, net [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	3,000	2,794
Goodwill [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	47	103
Intangible assets, net [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	1,436	1,493
Other noncurrent assets [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	0	14
Accounts payable [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	(59)	(48)
Accrued liabilities [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	(14)	(36)
Current deferred revenue [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	(62)	(45)
Noncurrent deferred income taxes [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	0	(13)
Asset retirement obligation [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	(93)	(94)
Noncurrent deferred revenue associated with customer advance payments [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	$ (331)	$ (395)
Gulfstar One [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	51.00%
Gulfstar One [Member] | Estimated Remaining Construction Costs For Variable Interest Entity [Member]
Variable Interest Entity [Line Items]
Estimated remaining construction costs	$ 130
Constitution Pipeline Company Llc [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	41.00%
Constitution Pipeline Company Llc [Member] | Estimated Remaining Construction Costs For Variable Interest Entity [Member]
Variable Interest Entity [Line Items]
Estimated remaining construction costs	$ 571
Cardinal Gas Services LLC [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	66.00%
Jackalope Gas Gathering Services LLC [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	50.00%

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transaction [Line Items]
Related Party Transaction, Purchases from Related Party	$ 187	$ 197	$ 161
Related party transactions, payable	12	13
Related Party Transaction, Expenses from Transactions with Related Party	64	65	67
Common Management Transaction [Member]
Related Party Transaction [Line Items]
Revenue from Related Parties	$ 111	$ 115	$ 131

Investing Activities (Details)

Investing Activities (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended	12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 20, 2012	Jun. 30, 2013
Schedule of Investments [Line Items]
Gain on remeasurement of equity-method investment					$ 0	$ 2,544	$ 0
Impairment of equity-method investments					1,359	0	0
Equity earnings (losses)					335	144	134
Investment Income, Nonoperating					27	43	81
Equity Method Investments		$ 7,336			7,336	8,400
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity		2,400			2,400	3,700
Equity Method Investment, payments to purchase or contributions					595	482	455
Equity method investment, dividends or distributions					633	440	247
Special distribution from equity-method investment					396	0	0
Contribution to equity-method investment for repayment of debt					248	0	0
Special distribution repayable to equity-method investment		149			149	0
Summarized Financial Position of Equity Method Investments
Current assets		773			773	599
Noncurrent assets		9,549			9,549	9,135
Current liabilities		(633)			(633)	(850)
Noncurrent liabilities		(1,450)			(1,450)	(954)
Summarized Results of Operations of Equity Method Investments
Gross revenue					1,707	1,623	2,406
Operating income					690	534	699
Net income					611	460	627
Delaware Basin Gas Gathering System [Member]
Schedule of Investments [Line Items]
Equity Method Investments		$ 977			$ 977	1,478
Equity Method Investment, Ownership Percentage		50.00%			50.00%
Equity Method Investment, payments to purchase or contributions					$ 57	20	0
Equity method investment, dividends or distributions					33	0	0
Appalachia Midstream Investments [Member]
Schedule of Investments [Line Items]
Equity Method Investments	[1]	$ 2,464			$ 2,464	3,033
Equity Method Investment, Ownership Percentage		45.00%			45.00%
Equity Method Investment, payments to purchase or contributions					$ 93	84	0
Equity method investment, dividends or distributions					219	130	0
Utica East Ohio Midstream, LLC [Member]
Schedule of Investments [Line Items]
Equity Method Investments	[2]	$ 1,525			$ 1,525	1,411
Equity Method Investment, Ownership Percentage		62.00%			62.00%
Equity Method Investment, payments to purchase or contributions	[3]				$ 357	57	0
Equity method investment, dividends or distributions					42	0	0
Discovery Producer Services LLC [Member]
Schedule of Investments [Line Items]
Equity Method Investments		$ 602			$ 602	602
Equity Method Investment, Ownership Percentage		60.00%			60.00%
Equity Method Investment, payments to purchase or contributions					$ 35	106	193
Equity method investment, dividends or distributions					116	36	12
Laurel Mountain Midstream, LLC [Member]
Schedule of Investments [Line Items]
Equity Method Investments		$ 391			$ 391	459
Equity Method Investment, Ownership Percentage		69.00%			69.00%
Equity method investment, dividends or distributions					$ 31	39	0
Overland Pass Pipeline Company LLC [Member]
Schedule of Investments [Line Items]
Equity Method Investments		$ 445			$ 445	453
Equity Method Investment, Ownership Percentage		50.00%			50.00%
Equity method investment, dividends or distributions					$ 45	27	27
Caiman Energy II, LLC [Member]
Schedule of Investments [Line Items]
Equity Method Investments		$ 418			$ 418	432
Equity Method Investment, Ownership Percentage		58.00%			58.00%
Equity Method Investment, payments to purchase or contributions					$ 0	175	192
Equity method investment, dividends or distributions					33	13	0
Gulfstream Natural Gas System, L.L.C.[Member]
Schedule of Investments [Line Items]
Equity Method Investments		$ 293			$ 293	317
Equity Method Investment, Ownership Percentage		50.00%			50.00%
Equity method investment, dividends or distributions					$ 88	81	81
Special distribution from equity-method investment					396
Contribution to equity-method investment for repayment of debt					248
Special distribution repayable to equity-method investment		$ 149			149
Access Midstream Partners [Member]
Schedule of Investments [Line Items]
Equity earnings (losses)						(7)	93
Income (loss) from investments							$ 31
Equity Method Investment, Ownership Percentage							23.00%		24.00%
Equity Method Investment, payments to purchase or contributions								$ 2,190
Equity method investment, dividends or distributions					0	64	$ 93
Access Midstream Partners [Member] | Adjustment For Amortization Of Difference Between Carrying Amount And Underlying Equity [Member]
Schedule of Investments [Line Items]
Equity earnings (losses)				$ (30)			(63)
Other [Member]
Schedule of Investments [Line Items]
Equity Method Investments		221			221	215
Equity Method Investment, payments to purchase or contributions					53	40	70
Equity method investment, dividends or distributions					26	50	34
Bluegrass Pipeline [Member]
Schedule of Investments [Line Items]
Equity earnings (losses)						(67)
Moss Lake [Member]
Schedule of Investments [Line Items]
Equity earnings (losses)						(4)
Former Venezuela Operations [Member]
Schedule of Investments [Line Items]
Investment Income, Nonoperating					27	41	$ 50
Equity-Method Investment Debt Due November 1, 2015 [Member] | Gulfstream Natural Gas System, L.L.C.[Member]
Schedule of Investments [Line Items]
Equity-method investment debt		500			500
Equity-Method Investment Debt Due June 1, 2016 [Member] | Gulfstream Natural Gas System, L.L.C.[Member]
Schedule of Investments [Line Items]
Equity-method investment debt		$ 300			$ 300
Additional Investment [Member] | Utica East Ohio Midstream, LLC [Member]
Schedule of Investments [Line Items]
Equity Method Investment, Ownership Percentage		13.00%			13.00%
Access Midstream Partners Acquisition [Member]
Schedule of Investments [Line Items]
Gain on remeasurement of equity-method investment						2,544
Access Midstream Partners Acquisition [Member] | Income Loss From Equity Method Investment [Member]
Schedule of Investments [Line Items]
Business Combination, Integration Related Costs						$ 19
Williams Partners L.P. [Member] | Income Loss From Equity Method Investment [Member] | Appalachia Midstream Investments [Member]
Schedule of Investments [Line Items]
Equity earnings (losses)					$ (19)
Williams Partners L.P. [Member] | Impairment Of Equity-Method Investments [Member] | Delaware Basin Gas Gathering System [Member]
Schedule of Investments [Line Items]
Impairment of equity-method investments		$ 45	$ 458
Williams Partners L.P. [Member] | Impairment Of Equity-Method Investments [Member] | Appalachia Midstream Investments [Member]
Schedule of Investments [Line Items]
Impairment of equity-method investments		559	$ 3
Williams Partners L.P. [Member] | Impairment Of Equity-Method Investments [Member] | Utica East Ohio Midstream, LLC [Member]
Schedule of Investments [Line Items]
Impairment of equity-method investments		241
Williams Partners L.P. [Member] | Impairment Of Equity-Method Investments [Member] | Laurel Mountain Midstream, LLC [Member]
Schedule of Investments [Line Items]
Impairment of equity-method investments		$ 45
[1]	Includes equity-method investments in multiple gathering systems in the Marcellus Shale with an approximate average 45 percent interest.
[2]	WPZ acquired an approximate 13 percent additional interest in UEOM in 2015. (See Note 2 – Acquisitions).
[3]	2015 includes additional interest in UEOM acquired by WPZ. (See Note 2 – Acquisitions.)

Other Income and Expenses (Deta

Other Income and Expenses (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other income (expense) - net [Member] | Williams Partners [Member]
Segment Reporting Information [Line Items]
Impairment of certain assets		$ 145	$ 52	$ 0
Amortization of regulatory assets associated with asset retirement obligations		33	33	30
Contingency gain settlement	[1]	0	(154)	0
Net gain related to partial acreage dedication release		0	(12)	0
Loss related to sale of certain assets		0	10	0
Other income (expense) - net [Member] | Williams Partners [Member] | Asset Impairment for Regulatory Action [Member]
Segment Reporting Information [Line Items]
Impairment of certain assets		0	(3)	12
Insurance recoveries		0	0	(16)
Other income (expense) - net [Member] | Williams Partners [Member] | Producer Claim [Member]
Segment Reporting Information [Line Items]
Loss associated with a producer claim		0	0	25
Other income (expense) - net [Member] | Williams NGL & Petchem Services [Member]
Segment Reporting Information [Line Items]
Impairment of certain assets		64	0	20
Net insurance recoveries - Geismar incident [Member] | Williams Partners [Member] | Geismar Incident [Member]
Segment Reporting Information [Line Items]
Insurance recoveries		(126)	(246)	(50)
Insurable expenses in excess of our deductibles			14	10
Selling, general and administrative expenses [Member] | Williams Partners [Member] | Acquisition and Merger [Member]
Segment Reporting Information [Line Items]
Business combination, acquisition related costs		26	27
Selling, general and administrative expenses [Member] | Williams Partners [Member] | Acquisition [Member]
Segment Reporting Information [Line Items]
Business combination, acquisition related costs			16
Selling, general and administrative expenses [Member] | Williams Partners [Member] | Transition [Member]
Segment Reporting Information [Line Items]
Business combination, integration related costs		9	15
Selling, general and administrative expenses [Member] | Other Segment [Member] | Other Restructuring [Member]
Segment Reporting Information [Line Items]
Business combination, integration related costs		32	10
Strategic alternative costs		30
Selling, general and administrative expenses [Member] | Williams NGL & Petchem Services [Member] | Bluegrass Pipeline Company Llc [Member]
Segment Reporting Information [Line Items]
Project development costs			18
Operation and maintenance [Member] | Williams Partners [Member] | Geismar Incident [Member]
Segment Reporting Information [Line Items]
Insurance deductible expense				13
Operation and maintenance [Member] | Williams Partners [Member] | Transition [Member]
Segment Reporting Information [Line Items]
Business combination, integration related costs		12	15
Interest expense [Member] | Acquisition [Member]
Segment Reporting Information [Line Items]
Business combination, acquisition related costs			9
Interest expense [Member] | Merger [Member]
Segment Reporting Information [Line Items]
Business combination, acquisition related costs		2
Service revenues [Member] | Williams Partners [Member]
Segment Reporting Information [Line Items]
Minimum volume commitment fees		239	167
Product costs [Member] | Williams Partners [Member]
Segment Reporting Information [Line Items]
Inventory Write-down		6	27
Other income (expense) - net [Member] | Williams Partners [Member]
Segment Reporting Information [Line Items]
Allowance for funds used during construction, capitalized cost of equity		95	$ 44	$ 22
Gain on extinguishment of debt		$ 14
[1]	In November 2014, we settled a claim arising from the resolution of a contingent gain related to claims associated with the purchase of a business in a prior period. Pursuant to the settlement, we received $154 million in cash, all of which was recognized as a gain in the fourth quarter of 2014.

Provision (Benefit) for Incom56

Provision (Benefit) for Income Taxes Tax Provison (Benefit) Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current :
Federal	$ 0	$ (9)	$ (17)
State	(7)	2	7
Foreign	(55)	10	(13)
Total	(62)	3	(23)
Deferred:
Federal	(317)	1,108	348
State	(25)	119	40
Foreign	5	19	36
Total	(337)	1,246	424
Provision (benefit) for income taxes	$ (399)	$ 1,249	$ 401

Provision (Benefit) for Incom57

Provision (Benefit) for Income Taxes Reconciliations to Recorded Tax Provision (Benefit) Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Effective Income Tax Rate Reconciliation [Abstract]
Provision (benefit) at statutory rate	$ (600)	$ 1,255	$ 378
Increases (decreases) in taxes resulting from:
Impact of nontaxable noncontrolling interests	263	(75)	(78)
State income taxes (net of federal benefit)	(21)	82	26
Foreign operations – net	8	(11)	(32)
Taxes on undistributed earnings of foreign subsidiaries – net	0	(37)	99
Translation adjustment of certain unrecognized tax benefits	(71)	0	0
Other – net	22	35	8
Provision (benefit) for income taxes	$ (399)	$ 1,249	$ 401

Provision (Benefit) for Incom58

Provision (Benefit) for Income Taxes Deferred Tax Table (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred income tax liabilities:
Property, plant, and equipment	$ 4	$ 4
Investments	5,272	5,472
Other	15	10
Total deferred income tax liabilities	5,291	5,486
Deferred income tax assets:
Accrued liabilities	150	178
Minimum tax credits	139	137
Foreign tax credit	193	251
Federal loss carryovers	485	134
State losses and credits	296	250
Other	42	97
Total deferred income tax assets	1,305	1,047
Less valuation allowance	190	206
Net deferred income tax assets	1,115	841
Overall net deferred income tax liabilities	$ 4,176	$ 4,645

Provision (Benefit) for Incom59

Provision (Benefit) for Income Taxes Reconciliation of Unrecognized Tax Benefits Table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 89	$ 66
Additions based on tax positions related to the current year	0	11
Additions for tax positions of prior years	2	12
Reductions for tax positions of prior years	0	0
Settlement with taxing authorities	0	0
Changes due to currency translation	(36)	0
Balance at end of period	$ 55	$ 89

Provision (Benefit) for Incom60

Provision (Benefit) for Income Taxes Textuals (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Contingency [Line Items]
Foreign income (loss) in Income from continuing operations before income taxes	$ 20	$ 102	$ 119
Impairment Loss	2,700
Gain on remeasurement of equity-method investment	0	2,544	0
Taxes on undistributed earnings of foreign subsidiaries – net	0	(37)	99
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	(31)	(18)	(24)
Minimum tax credits	139	137
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	193	251
Employee Share-based Compensation Tax Benefit Excluded From Deferred Income Tax Assets	23	23
Cash payments for income taxes (net of refunds and including discontinued operations)	(136)	29	(50)
Unrecognized tax benefits	55	89	66
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	51
Total interest and penalties recognized as part of income tax provision	22	8	$ 9
Total interest and penalties accrued as uncertain tax positions	2	$ 24
Foreign tax credit [Member]
Income Tax Contingency [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	139
Unrecognized Tax Benefits Income Tax Penalties And Interest Expense Due To Currency Fluctuations [Member]
Income Tax Contingency [Line Items]
Total interest and penalties recognized as part of income tax provision	35
Federal [Member] | Federal Net Operating Loss And Charitable Contribution Carryforwards [Member]
Income Tax Contingency [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	$ 1,500

Earnings (Loss) Per Common Sh61

Earnings (Loss) Per Common Share from Continuing Operations (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Earnings (loss) per common share from continuing operations
Income (loss) from continuing operations attributable to The Williams Companies, Inc. available to common stockholders for basic and diluted earnings (loss) per common share	$ (571)		$ 2,110	$ 441
Basic weighted-average shares	749,271		719,325	682,948
Diluted weighted-average shares	749,271	[1]	723,641	687,185
Earnings (loss) per common share from continuing operations:
Basic	$ (0.76)		$ 2.93	$ 0.65
Diluted	$ (0.76)		$ 2.91	$ 0.64
Nonvested restricted stock units [Member]
Effect of dilutive securities:
Incremental common shares attributable to share-based payment arrangements under effects of dilutive securities item	0		2,234	1,995
Earnings (loss) per common share from continuing operations (Textuals) [Abstract]
Number of weighted-average shares excluded from computation of diluted earnings per common share	1,700
Stock options [Member]
Effect of dilutive securities:
Incremental common shares attributable to share-based payment arrangements under effects of dilutive securities item	0		2,064	2,149
Earnings (loss) per common share from continuing operations (Textuals) [Abstract]
Number of weighted-average shares excluded from computation of diluted earnings per common share	1,500
Convertible debentures [Member]
Effect of dilutive securities:
Incremental dilutive shares, Convertible debt	0		18	93
[1]	For the year ended December 31, 2015, 1.7 million weighted-average nonvested restricted stock units and 1.5 million weighted-average stock options have been excluded from the computation of diluted earnings (loss) per common share as their inclusion would be antidilutive due to our loss from continuing operations attributable to The Williams Companies, Inc.

EBPs Obligation Rollforward (De

EBPs Obligation Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Plan, Defined Benefit [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	$ 1,544	$ 1,384
Service cost	59	40	$ 44
Interest cost	58	62	51
Plan participants' contributions	0	0
Benefits paid	(101)	(86)
Plan amendment	0	0
Actuarial loss (gain)	(91)	144
Settlements	(5)	(3)
Curtailments	0	0
Other	0	3
Benefit obligation at end of year	1,464	1,544	1,384
Other Postretirement Benefits [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	233	213
Service cost	2	2	2
Interest cost	9	10	11
Plan participants' contributions	2	2
Benefits paid	(13)	(14)
Plan amendment	0	1
Actuarial loss (gain)	(31)	21
Settlements	0	(1)
Curtailments	0	(1)
Other	0	0
Benefit obligation at end of year	$ 202	$ 233	$ 213

EBP Asset rollforward and B.S.

EBP Asset rollforward and B.S. classification (Details 1) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Change in plan assets:
Fair value of plan assets at beginning of year	$ 1,293	$ 1,241
Actual return on plan assets	(11)	78
Employer contributions	65	63
Plan participants' contributions	0	0
Benefits paid	(101)	(86)
Settlements	(5)	(3)
Fair value of plan asets at end of year	1,241	1,293
Funded status - underfunded	(223)	(251)
Accumulated benefit obligation	1,432	1,516
Underfunded/overfunded status of our pension plans and other postretirement benefit plans
Current liabilities	(2)	(2)
Noncurrent liabilities	(221)	(249)
Amounts included in accumulated other comprehensive income (loss):
Prior service credit	0	0
Net actuarial loss	(544)	(593)
Other Postretirement Benefits [Member]
Change in plan assets:
Fair value of plan assets at beginning of year	208	201
Actual return on plan assets	(1)	13
Employer contributions	5	6
Plan participants' contributions	2	2
Benefits paid	(13)	(14)
Settlements	0	0
Fair value of plan asets at end of year	201	208
Funded status - underfunded	(1)	(25)
Underfunded/overfunded status of our pension plans and other postretirement benefit plans
Current liabilities	(7)	(7)
Noncurrent liabilities		(18)
Noncurrent assets	6
Amounts included in accumulated other comprehensive income (loss):
Prior service credit	11	17
Net actuarial loss	(18)	(28)
Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline
Prior service credit	19	30
Net actuarial gain (loss)	6	(4)
Net regulatory assets (liabilities)	$ (78)	$ (62)

EBP Net Periodic Benefit Cost &

EBP Net Periodic Benefit Cost & OCI (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits [Member]
Components of net periodic benefit cost:
Service cost	$ 59	$ 40	$ 44
Interest cost	58	62	51
Expected return on plan assets	(75)	(76)	(61)
Amortization of prior service cost (credit)	0	0	1
Amortization of net actuarial loss	42	39	60
Net actuarial (gain) loss from settlements and curtailments	2	1	0
Reclassification to regulatory liability	0	0	0
Net periodic benefit cost	86	66	95
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss):
Net actuarial gain (loss)	5	(142)	277
Prior service (cost) credit	0	0	0
Amortization of prior service cost (credit)	0	0	1
Amortization of net actuarial loss	42	39	60
Loss from settlements and curtailments	2	1	0
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss)	49	(102)	338
Amounts included in accumulated other comprehensive income (loss):
Prior service cost (credit) expected to be amortized in next fiscal year	0
Net actuarial (gain) loss expected to be amortized in next fiscal year	31
Other Postretirement Benefits [Member]
Components of net periodic benefit cost:
Service cost	2	2	2
Interest cost	9	10	11
Expected return on plan assets	(12)	(12)	(9)
Amortization of prior service cost (credit)	(17)	(20)	(12)
Amortization of net actuarial loss	2	0	4
Net actuarial (gain) loss from settlements and curtailments	0	(1)	0
Reclassification to regulatory liability	3	4	2
Net periodic benefit cost	(13)	(17)	(2)
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss):
Net actuarial gain (loss)	8	(18)	23
Prior service (cost) credit	0	(1)	23
Amortization of prior service cost (credit)	(6)	(8)	(4)
Amortization of net actuarial loss	2	0	1
Loss from settlements and curtailments	0	1	0
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss)	4	(26)	43
Other changes in plan assets and benefit obligations recognized in regulatory (assets) liabilities:
Net actuarial gain (loss) recognized in regulatory liabilities (assets)	10	(2)	62
Prior service credit (cost) recognized in regulatory liabilities (assets)	0	0	36
Amortization of net actuarial loss (gain) from regulatory assets (liabilities)	0	0	3
Amortization of prior service cost (credit) from regulatory assets (liabilities)	(11)	$ (12)	$ (8)
Amounts included in accumulated other comprehensive income (loss):
Prior service cost (credit) expected to be amortized in next fiscal year	(6)
Net actuarial (gain) loss expected to be amortized in next fiscal year	0
Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline
Prior service cost (credit) expected to be amortized in next fiscal year	(9)
Net actuarial (gain) loss expected to be amortized in next fiscal year	$ 0

EBP Key Assumptions (Details 3)

EBP Key Assumptions (Details 3) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits [Member]
Weighted average assumptions utilized to determine benefit obligations
Rate of compensation increase	4.88%	4.62%
Discount rate	4.38%	3.96%
Weighted average assumptions utilized to determine net periodic benefit cost
Discount rate	3.96%	4.68%	3.43%
Expected long-term rate of return on plan assets	6.38%	6.85%	5.90%
Rate of compensation increase	4.62%	4.56%	4.57%
Other Postretirement Benefits [Member]
Weighted average assumptions utilized to determine benefit obligations
Discount rate	4.50%	4.12%
Weighted average assumptions utilized to determine net periodic benefit cost
Discount rate	4.12%	4.80%	3.97%
Expected long-term rate of return on plan assets	5.70%	6.11%	5.26%
One percentage point change in assumed health care cost trend rates effects
Effect on total of service and interest cost components, Point increase	$ 0
Effect on total of service and interest cost components, Point decrease	0
Effect on other postretirement benefit obligation, Point increase	7
Effect on other postretirement benefit obligation, Point decrease	$ (6)
Health care cost trend rate assumed for next fiscal year	7.90%
Direction and pattern of change for assumed health care cost trend rate	decreases
Ultimate health care cost trend rate	4.50%
Year that rate reaches ultimate trend rate	2,025

EBP Plan Assets (Details 4)

EBP Plan Assets (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Maximum percentage of total stock portfolio invested in the common stock of any one corporation	5.00%
Maximum percentage of portfolio invested in fixed income securities of any one issuer with exception of bond index funds and U. S. government guaranteed and agency securities	5.00%
Each investment manager responsibility to manage the plans' funds, minimum	1.00%
Each investment manager responsibility to manage the plans' funds, maximum	28.00%
Fair value, plan assets, Level 1 to Level 2 transfers, amount	$ 0	$ 0
Fair value, plan assets, Level 2 to Level 1 transfers, amount	$ 0	0
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period	30 days
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period	10 days
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of active investment managers managing plan funds	12
Number of passive investment managers managing plan funds	1
Fair value, plan assets, Level 1 to Level 2 transfers, amount	$ 0
Fair value, plan assets, Level 2 to Level 1 transfers, amount	0
Fair values of plan assets
Total assets at fair value	$ 1,241	$ 1,293	$ 1,241
Pension Benefits [Member] | Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset target allocation	60.00%
Pension Benefits [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan asset target allocation	40.00%
Weighted average duration of fixed income security portfolio	8 years	6 years
Pension Benefits [Member] | Plan assets within fair value hierarchy [Member]
Fair values of plan assets
Total assets at fair value	$ 465	$ 770
Pension Benefits [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	8	25
Pension Benefits [Member] | U.S. large cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	83	221
Pension Benefits [Member] | U.S. small cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	64	139
Pension Benefits [Member] | International developed markets large cap growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value		60
Pension Benefits [Member] | U.S. Treasury securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	65	31
Pension Benefits [Member] | Government and municipal bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	8
Pension Benefits [Member] | Mortgage and asset-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	87	65
Pension Benefits [Member] | Corporate bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	145	222
Pension Benefits [Member] | Insurance company investment contracts and other [Member]
Fair values of plan assets
Total assets at fair value	5	7
Pension Benefits [Member] | Equities - U.S. large cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	367	189
Pension Benefits [Member] | Equities - International small cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	27	24
Pension Benefits [Member] | Equities - International emerging markets [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	50
Pension Benefits [Member] | Equities - International developed markets [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	153
Pension Benefits [Member] | Equities - Emerging markets value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value		27
Pension Benefits [Member] | Equities - Emerging markets growth [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value		19
Pension Benefits [Member] | Equities - International developed markets large cap value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value		101
Pension Benefits [Member] | Fixed income - U.S. long duration [Member] | Commingled investment funds - fixed income [Member]
Fair values of plan assets
Total assets at fair value	95
Pension Benefits [Member] | Fixed income - Corporate bonds [Member] | Commingled investment funds - fixed income [Member]
Fair values of plan assets
Total assets at fair value	84	163
Pension Benefits [Member] | Level 1 [Member]
Fair values of plan assets
Total assets at fair value	220	416
Pension Benefits [Member] | Level 1 [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	8	25
Pension Benefits [Member] | Level 1 [Member] | U.S. large cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	83	221
Pension Benefits [Member] | Level 1 [Member] | U.S. small cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	64	139
Pension Benefits [Member] | Level 1 [Member] | International developed markets large cap growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value		0
Pension Benefits [Member] | Level 1 [Member] | U.S. Treasury securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	65	31
Pension Benefits [Member] | Level 1 [Member] | Government and municipal bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0
Pension Benefits [Member] | Level 1 [Member] | Mortgage and asset-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 1 [Member] | Corporate bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 1 [Member] | Insurance company investment contracts and other [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 2 [Member]
Fair values of plan assets
Total assets at fair value	245	354
Pension Benefits [Member] | Level 2 [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 2 [Member] | U.S. large cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 2 [Member] | U.S. small cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 2 [Member] | International developed markets large cap growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value		60
Pension Benefits [Member] | Level 2 [Member] | U.S. Treasury securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 2 [Member] | Government and municipal bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	8
Pension Benefits [Member] | Level 2 [Member] | Mortgage and asset-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	87	65
Pension Benefits [Member] | Level 2 [Member] | Corporate bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	145	222
Pension Benefits [Member] | Level 2 [Member] | Insurance company investment contracts and other [Member]
Fair values of plan assets
Total assets at fair value	5	7
Pension Benefits [Member] | Level 3 [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | U.S. large cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | U.S. small cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | International developed markets large cap growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value		0
Pension Benefits [Member] | Level 3 [Member] | U.S. Treasury securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | Government and municipal bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0
Pension Benefits [Member] | Level 3 [Member] | Mortgage and asset-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | Corporate bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | Insurance company investment contracts and other [Member]
Fair values of plan assets
Total assets at fair value	$ 0	0
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Proportion of assets subjected to income tax	38.00%
Number of active investment managers managing plan funds	4
Number of passive investment managers managing plan funds	1
Fair values of plan assets
Total assets at fair value	$ 201	$ 208	$ 201
Other Postretirement Benefits [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average duration of fixed income security portfolio	7 years	5 years
Other Postretirement Benefits [Member] | Plan assets within fair value hierarchy [Member]
Fair values of plan assets
Total assets at fair value	$ 122	$ 156
Other Postretirement Benefits [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	11	13
Other Postretirement Benefits [Member] | U.S. large cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	37	53
Other Postretirement Benefits [Member] | U.S. small cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	20	28
Other Postretirement Benefits [Member] | International developed markets large cap growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	10	15
Other Postretirement Benefits [Member] | Emerging markets growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	1	3
Other Postretirement Benefits [Member] | U.S. Treasury securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	7	3
Other Postretirement Benefits [Member] | Government and municipal bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	12	11
Other Postretirement Benefits [Member] | Mortgage and asset-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	9	7
Other Postretirement Benefits [Member] | Corporate bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	15	23
Other Postretirement Benefits [Member] | Equities - U.S. large cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	37	19
Other Postretirement Benefits [Member] | Equities - International small cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	3	2
Other Postretirement Benefits [Member] | Equities - International emerging markets [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	5
Other Postretirement Benefits [Member] | Equities - International developed markets [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	16
Other Postretirement Benefits [Member] | Equities - Emerging markets value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value		3
Other Postretirement Benefits [Member] | Equities - Emerging markets growth [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value		2
Other Postretirement Benefits [Member] | Equities - International developed markets large cap value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value		10
Other Postretirement Benefits [Member] | Fixed income - U.S. long duration [Member] | Commingled investment funds - fixed income [Member]
Fair values of plan assets
Total assets at fair value	10
Other Postretirement Benefits [Member] | Fixed income - Corporate bonds [Member] | Commingled investment funds - fixed income [Member]
Fair values of plan assets
Total assets at fair value	8	16
Other Postretirement Benefits [Member] | Level 1 [Member]
Fair values of plan assets
Total assets at fair value	76	98
Other Postretirement Benefits [Member] | Level 1 [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	11	13
Other Postretirement Benefits [Member] | Level 1 [Member] | U.S. large cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	37	53
Other Postretirement Benefits [Member] | Level 1 [Member] | U.S. small cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	20	28
Other Postretirement Benefits [Member] | Level 1 [Member] | International developed markets large cap growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	1	0
Other Postretirement Benefits [Member] | Level 1 [Member] | Emerging markets growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	0	1
Other Postretirement Benefits [Member] | Level 1 [Member] | U.S. Treasury securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	7	3
Other Postretirement Benefits [Member] | Level 1 [Member] | Government and municipal bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 1 [Member] | Mortgage and asset-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 1 [Member] | Corporate bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 2 [Member]
Fair values of plan assets
Total assets at fair value	46	58
Other Postretirement Benefits [Member] | Level 2 [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 2 [Member] | U.S. large cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 2 [Member] | U.S. small cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 2 [Member] | International developed markets large cap growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	9	15
Other Postretirement Benefits [Member] | Level 2 [Member] | Emerging markets growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	1	2
Other Postretirement Benefits [Member] | Level 2 [Member] | U.S. Treasury securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 2 [Member] | Government and municipal bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	12	11
Other Postretirement Benefits [Member] | Level 2 [Member] | Mortgage and asset-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	9	7
Other Postretirement Benefits [Member] | Level 2 [Member] | Corporate bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	15	23
Other Postretirement Benefits [Member] | Level 3 [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | U.S. large cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | U.S. small cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | International developed markets large cap growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | Emerging markets growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | U.S. Treasury securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | Government and municipal bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | Mortgage and asset-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | Corporate bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	$ 0	$ 0

EBP Benefit Pymts & Defined Con

EBP Benefit Pymts & Defined Contribution Plans (Details 6) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Employer's contributions charged to expense under defined contribution plans	$ 39	$ 39	$ 27
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected total plans contribution, approximate	7
Expected benefit payments
2,016	13
2,017	13
2,018	13
2,019	13
2,020	14
2021-2025	66
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected total plans contribution, approximate	62
Expected benefit payments
2,016	95
2,017	102
2,018	105
2,019	106
2,020	110
2021-2025	578
Nonqualified Pension Benefits - Supplemental Employee Retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected total plans contribution, approximate	2
Tax-qualified Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected total plans contribution, approximate	$ 60

Inventories (Details)

Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Inventory, Net [Abstract]
Natural gas liquids, olefins, and natural gas in underground storage	$ 57	$ 150
Materials, supplies, and other	70	81
Inventories, Total	$ 127	$ 231

Property, Plant, and Equipmen69

Property, Plant, and Equipment (Details PPE) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant, and Equipment
Total property, plant, and equipment, at cost		$ 39,039	$ 36,435
Accumulated depreciation and amortization		(9,460)	(8,354)
Property, plant, and equipment - net		29,579	28,081
Depreciation and amortization		1,382	967	$ 752
Nonregulated [Member] | Natural gas gathering and processing facilities [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost		$ 20,789	18,749
Nonregulated [Member] | Natural gas gathering and processing facilities [Member] | Minimum [Member]
Property, Plant, and Equipment
Property, Plant and Equipment, Useful Life	[1]	5 years
Nonregulated [Member] | Natural gas gathering and processing facilities [Member] | Maximum [Member]
Property, Plant, and Equipment
Property, Plant and Equipment, Useful Life	[1]	40 years
Nonregulated [Member] | Construction in Progress [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost		$ 1,366	2,648
Nonregulated [Member] | Other Capitalized Property Plant and Equipment [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost		$ 2,170	1,850
Nonregulated [Member] | Other Capitalized Property Plant and Equipment [Member] | Minimum [Member]
Property, Plant, and Equipment
Property, Plant and Equipment, Useful Life	[1]	2 years
Nonregulated [Member] | Other Capitalized Property Plant and Equipment [Member] | Maximum [Member]
Property, Plant, and Equipment
Property, Plant and Equipment, Useful Life	[1]	45 years
Regulated [Member] | Natural gas transmission facilities [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost		$ 12,189	10,867
Regulated [Member] | Natural gas transmission facilities [Member] | Minimum [Member]
Property, Plant, and Equipment
Property, Plant, and Equipment, Depreciation Rate	[1]	1.20%
Regulated [Member] | Natural gas transmission facilities [Member] | Maximum [Member]
Property, Plant, and Equipment
Property, Plant, and Equipment, Depreciation Rate	[1]	6.97%
Regulated [Member] | Construction in Progress [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost		$ 941	985
Regulated [Member] | Other Capitalized Property Plant and Equipment [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost		$ 1,584	1,336
Regulated [Member] | Other Capitalized Property Plant and Equipment [Member] | Minimum [Member]
Property, Plant, and Equipment
Property, Plant and Equipment, Useful Life	[1]	5 years
Property, Plant, and Equipment, Depreciation Rate	[1]	1.35%
Regulated [Member] | Other Capitalized Property Plant and Equipment [Member] | Maximum [Member]
Property, Plant, and Equipment
Property, Plant and Equipment, Useful Life	[1]	45 years
Property, Plant, and Equipment, Depreciation Rate	[1]	33.33%
Regulated [Member] | Excess Of Original Cost Of Regulated Facilities [Member]
Property, Plant, and Equipment
Property, plant, and equipment - net		$ 706	$ 746
Period of straight-line amortization		40 years
[1]	Estimated useful life and depreciation rates are presented as of December 31, 2015. Depreciation rates and estimated useful lives for regulated assets are prescribed by the FERC.

Property, Plant, and Equipmen70

Property, Plant, and Equipment (Details ARO) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Asset Retirement Obligations
Asset Retirement Obligations, Noncurrent		$ 858	$ 791
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance		831	561
Liabilities incurred		42	101
Liabilities settled	[1]	(3)	(21)
Accretion expense		60	44
Revisions	[2]	(15)	146
Ending balance		915	831
Charges related to leak at underground storage facility [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Liabilities settled			$ (7)
Asset Retirement Obligation Costs [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Transco's annual funding commitment for ARO		$ 36
[1]	For 2014, liabilities settled include $7 million related to the abandonment of certain of Transco’s natural gas storage caverns that are associated with a leak in 2010.
[2]	Several factors are considered in the annual review process, including inflation rates, current estimates for removal cost, discount rates, and the estimated remaining useful life of the assets. The 2015 revisions reflect changes in removal cost estimates and the estimated remaining useful life of assets, a decrease in the inflation rate, and increases in the discount rates used in the annual review process. The 2014 revisions primarily reflect an increase in the estimated retirement costs for our offshore pipelines, an increase in the inflation rate, and decreases in the discount rates used in the annual review process.

Goodwill (Details)

Goodwill (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Goodwill, beginning of period		$ 1,120
Impairment of goodwill	$ (1,098)	(1,098)	$ 0	$ 0
Goodwill, end of period	47	47	1,120
Williams Partners [Member]
Goodwill [Line Items]
Goodwill, beginning of period		1,120
Goodwill, Purchase Accounting Adjustments		25
Impairment of goodwill		(1,098)
Goodwill, end of period	$ 47	$ 47	$ 1,120

Other Intangible Assets (Detail

Other Intangible Assets (Details) - USD ($) $ in Millions	1 Months Ended	2 Months Ended	3 Months Ended		4 Months Ended	6 Months Ended	12 Months Ended
	May. 31, 2015	Feb. 17, 2012	Sep. 30, 2015	Mar. 31, 2015	Apr. 27, 2012	Jul. 02, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jul. 01, 2014
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets							$ 353	$ 209	$ 60
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months							354
Finite-Lived Intangible Assets, Amortization Expense, Year Two							354
Finite-Lived Intangible Assets, Amortization Expense, Year Three							354
Finite-Lived Intangible Assets, Amortization Expense, Year Four							354
Finite-Lived Intangible Assets, Amortization Expense, Year Five							354
Contractual customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross							10,633	10,763
Finite-Lived Intangible Assets, Accumulated Amortization							$ (663)	$ (310)
Access Midstream Partners Acquisition [Member]
Finite-Lived Intangible Assets [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles				$ (168)
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life						30 years
Acquired Finite-lived Intangible Asset, Weighted-Average Period before Renewal or Extension						17 years
Eagle Ford Gathering System [Member]
Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 32
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	30 years
Acquired Finite-lived Intangible Asset, Weighted-Average Period before Renewal or Extension	10 years
Laser Acquisition [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		30 years
Acquired Finite-lived Intangible Asset, Weighted-Average Period before Renewal or Extension		9 years
Caiman Acquisition [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life					30 years
Acquired Finite-lived Intangible Asset, Weighted-Average Period before Renewal or Extension					18 years
Williams Partners [Member] | Access Midstream Partners Acquisition [Member]
Finite-Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles										$ 8,841
Williams Partners [Member] | Eagle Ford Gathering System [Member]
Finite-Lived Intangible Assets [Line Items]
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Intangibles			$ (20)

Accrued Liabilities (Details)

Accrued Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Accrued Liabilities, Current [Abstract]
Interest on debt	$ 284	$ 268
Employee costs	215	167
Special distribution repayable to Gulfstream (See Note 5 - Investing Activities)	149	0
Deferred income	94	82
Asset retirement obligations	57	40
Other, including other loss contingencies	279	343
Accrued Liabilities, Current	$ 1,078	$ 900

Long-Term Debt (Details)

Long-Term Debt (Details) - USD ($) $ in Millions		Dec. 31, 2015	Apr. 15, 2015	Mar. 03, 2015	Dec. 31, 2014	Jun. 24, 2014
Long-term Debt
Capital lease obligations		$ 1			$ 5
Debt issuance costs		(123)			(108)
Net unamortized debt premium (discount)		110			187
Total long-term debt, including current portion		23,988			20,784
Long-term debt due within one year		(176)			(4)
Long-term Debt and Capital Lease Obligations		23,812			20,780
Transcontinental Gas Pipe Line Company, LLC [Member] | 6.4% Senior Unsecured Notes due 2016 [Member]
Long-term Debt
Long-term debt	[1]	$ 200			200
Long-term debt interest rate		6.40%
Transcontinental Gas Pipe Line Company, LLC [Member] | 6.05% Senior Unsecured Notes due 2018 [Member]
Long-term Debt
Long-term debt		$ 250			250
Long-term debt interest rate		6.05%
Transcontinental Gas Pipe Line Company, LLC [Member] | 7.08% Debentures due 2026 [Member]
Long-term Debt
Long-term debt		$ 8			8
Long-term debt interest rate		7.08%
Transcontinental Gas Pipe Line Company, LLC [Member] | 7.25% Debentures due 2026 [Member]
Long-term Debt
Long-term debt		$ 200			200
Long-term debt interest rate		7.25%
Transcontinental Gas Pipe Line Company, LLC [Member] | 5.4% Senior Unsecured Notes due 2041 [Member]
Long-term Debt
Long-term debt		$ 375			375
Long-term debt interest rate		5.40%
Transcontinental Gas Pipe Line Company, LLC [Member] | 4.45% Senior Unsecured Notes due 2042 [Member]
Long-term Debt
Long-term debt		$ 400			400
Long-term debt interest rate		4.45%
Northwest Pipeline LLC [Member] | 7% Senior Unsecured Notes due 2016 [Member]
Long-term Debt
Long-term debt		$ 175			175
Long-term debt interest rate		7.00%
Northwest Pipeline LLC [Member] | 5.95% Senior Unsecured Notes due 2017 [Member]
Long-term Debt
Long-term debt		$ 185			185
Long-term debt interest rate		5.95%
Northwest Pipeline LLC [Member] | 6.05% Senior Unsecured Notes due 2018 [Member]
Long-term Debt
Long-term debt		$ 250			250
Long-term debt interest rate		6.05%
Northwest Pipeline LLC [Member] | 7.125% Debentures due 2025 [Member]
Long-term Debt
Long-term debt		$ 85			85
Long-term debt interest rate		7.125%
The Williams Companies, Inc. [Member]
Long-term Debt
Credit facility loans		$ 650			370
The Williams Companies, Inc. [Member] | 7.875% Senior Unsecured Notes due 2021 [Member]
Long-term Debt
Long-term debt		$ 371			371
Long-term debt interest rate		7.875%
The Williams Companies, Inc. [Member] | 3.7% Senior Unsecured Notes due 2023 [Member]
Long-term Debt
Long-term debt		$ 850			850
Long-term debt interest rate		3.70%
The Williams Companies, Inc. [Member] | 4.55% Senior Unsecured Notes due 2024 [Member]
Long-term Debt
Long-term debt		$ 1,250			1,250
Long-term debt interest rate		4.55%				4.55%
The Williams Companies, Inc. [Member] | 7.5% Debentures due 2031 [Member]
Long-term Debt
Long-term debt		$ 339			339
Long-term debt interest rate		7.50%
The Williams Companies, Inc. [Member] | 7.75% Senior Unsecured Notes due 2031 [Member]
Long-term Debt
Long-term debt		$ 252			252
Long-term debt interest rate		7.75%
The Williams Companies, Inc. [Member] | 8.75% Senior Unsecured Notes due 2032 [Member]
Long-term Debt
Long-term debt		$ 445			445
Long-term debt interest rate		8.75%
The Williams Companies, Inc. [Member] | 5.75% Senior Unsecured Notes due 2044 [Member]
Long-term Debt
Long-term debt		$ 650			650
Long-term debt interest rate		5.75%				5.75%
The Williams Companies, Inc. [Member] | Various - 5.5% to 10.25% Senior Unsecured Notes and Debentures due 2019 to 2033 [Member]
Long-term Debt
Long-term debt		$ 55			55
The Williams Companies, Inc. [Member] | Various - 5.5% to 10.25% Senior Unsecured Notes and Debentures due 2019 to 2033 Minimum Interest Rate [Member]
Long-term Debt
Long-term debt interest rate		5.50%
The Williams Companies, Inc. [Member] | Various - 5.5% to 10.25% Senior Unsecured Notes and Debentures due 2019 to 2033 Maximum Interest Rate [Member]
Long-term Debt
Long-term debt interest rate		10.25%
Williams Partners L.P. [Member]
Long-term Debt
Credit facility loans		$ 1,310			640
Williams Partners L.P. [Member] | 3.8% Senior Unsecured Notes due 2015 [Member]
Long-term Debt
Long-term debt	[2]	$ 0			750
Long-term debt interest rate		3.80%
Williams Partners L.P. [Member] | 7.25% Senior Unsecured Notes due 2017 [Member]
Long-term Debt
Long-term debt		$ 600			600
Long-term debt interest rate		7.25%
Williams Partners L.P. [Member] | 5.25% Senior Unsecured Notes due 2020 [Member]
Long-term Debt
Long-term debt		$ 1,500			1,500
Long-term debt interest rate		5.25%
Williams Partners L.P. [Member] | 4.125% Senior Unsecured Notes due 2020 [Member]
Long-term Debt
Long-term debt		$ 600			600
Long-term debt interest rate		4.125%
Williams Partners L.P. [Member] | 4% Senior Unsecured Notes due 2021 [Member]
Long-term Debt
Long-term debt		$ 500			500
Long-term debt interest rate		4.00%
Williams Partners L.P. [Member] | 3.6% Senior Unsecured Notes due 2022 [Member]
Long-term Debt
Long-term debt		$ 1,250			0
Long-term debt interest rate		3.60%		3.60%
Williams Partners L.P. [Member] | 5.875% Senior Unsecured Notes due 2021 [Member]
Long-term Debt
Long-term debt		$ 0			750
Long-term debt interest rate		5.875%	5.875%
Williams Partners L.P. [Member] | 3.35% Senior Unsecured Notes due 2022 [Member]
Long-term Debt
Long-term debt		$ 750			750
Long-term debt interest rate		3.35%
Williams Partners L.P. [Member] | 6.125% Senior Unsecured Notes due 2022 [Member]
Long-term Debt
Long-term debt		$ 750			750
Long-term debt interest rate		6.125%
Williams Partners L.P. [Member] | 4.5% Senior Unsecured Notes due 2023 [Member]
Long-term Debt
Long-term debt		$ 600			600
Long-term debt interest rate		4.50%
Williams Partners L.P. [Member] | 4.875% Senior Unsecured Notes due 2023 [Member]
Long-term Debt
Long-term debt		$ 1,400			1,400
Long-term debt interest rate		4.875%
Williams Partners L.P. [Member] | 4.3% Senior Unsecured Notes Due 2024 [Member]
Long-term Debt
Long-term debt		$ 1,000			1,000
Long-term debt interest rate		4.30%
Williams Partners L.P. [Member] | 4.875% Senior Unsecured Notes due 2024 [Member]
Long-term Debt
Long-term debt		$ 750			750
Long-term debt interest rate		4.875%
Williams Partners L.P. [Member] | 3.9% Senior Unsecured Notes due 2025 [Member]
Long-term Debt
Long-term debt		$ 750			750
Long-term debt interest rate		3.90%
Williams Partners L.P. [Member] | 4% Senior Unsecured Notes due 2025 [Member]
Long-term Debt
Long-term debt		$ 750			0
Long-term debt interest rate		4.00%		4.00%
Williams Partners L.P. [Member] | 6.3% Senior Unsecured Notes due 2040 [Member]
Long-term Debt
Long-term debt		$ 1,250			1,250
Long-term debt interest rate		6.30%
Williams Partners L.P. [Member] | 5.8% Senior Unsecured Notes due 2043 [Member]
Long-term Debt
Long-term debt		$ 400			400
Long-term debt interest rate		5.80%
Williams Partners L.P. [Member] | 5.4% Senior Unsecured Notes Due 2044 [Member]
Long-term Debt
Long-term debt		$ 500			500
Long-term debt interest rate		5.40%
Williams Partners L.P. [Member] | 4.9% Senior Unsecured Notes due 2045 [Member]
Long-term Debt
Long-term debt		$ 500			500
Long-term debt interest rate		4.90%
Williams Partners L.P. [Member] | 5.1% Senior Unsecured Notes due 2045 [Member]
Long-term Debt
Long-term debt		$ 1,000			0
Long-term debt interest rate		5.10%		5.10%
Williams Partners L.P. [Member] | Variable Interest Term Loan due 2018 [Member]
Long-term Debt
Long-term debt		$ 850			$ 0
[1]	Presented as long-term debt at December 31, 2015, due to Transco’s intent and ability to refinance.
[2]	Presented as long-term debt at December 31, 2014, due to WPZ's intent and ability to refinance.

Long-Term Debt Maturities (Deta

Long-Term Debt Maturities (Details) $ in Millions	Dec. 31, 2015USD ($)
Aggregate minimum maturities of long-term debt
2,016	$ 175
2,017	785
2,018	1,350
2,019	32
2,020	$ 2,121

Long Term Debt Change of Contro

Long Term Debt Change of Control Provision (Details) - Access Midstream Partners Lp [Member] $ in Billions	Dec. 31, 2015USD ($)
Change Of Control Payment Percentage Of 101% [Line Items]
Debt Instrument, Face Amount	$ 2.9
Change Of Control Payment Percentage	1.01

Long-Term Debt Issuances and Re

Long-Term Debt Issuances and Retirements (Details) - USD ($) $ in Millions

Apr. 15, 2015

Feb. 15, 2015

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Jan. 22, 2016

Dec. 23, 2015

Mar. 03, 2015

Jun. 27, 2014

Jun. 24, 2014

Mar. 04, 2014

Debt Instrument [Line Items]

Repayments of Long-term Debt

$ 6,516

$ 1,828

$ 2,081

The Williams Companies, Inc. [Member] | 4.55% Senior Unsecured Notes due 2024 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 1,250

1,250

Long-term debt face amount

$ 1,250

Long-term debt interest rate

4.55%

4.55%

The Williams Companies, Inc. [Member] | 5.75% Senior Unsecured Notes due 2044 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 650

650

Long-term debt face amount

$ 650

Long-term debt interest rate

5.75%

5.75%

Williams Partners L.P. [Member] | 7.85% Senior Unsecured Notes Due 2026 [Member] | Subsequent Event [Member]

Debt Instrument [Line Items]

Long-term debt face amount

$ 1,000

Williams Partners L.P. [Member] | Variable interest Rate [Member]

Debt Instrument [Line Items]

Long-term debt

$ 850

Long-term debt interest rate

1.8531%

Williams Partners L.P. [Member] | 3.8% Senior Unsecured Notes due 2015 [Member]

Debt Instrument [Line Items]

Long-term debt retired

$ 750

Long-term debt interest rate

3.80%

Williams Partners L.P. [Member] | 3.9% Senior Unsecured Notes due 2025 [Member]

Debt Instrument [Line Items]

Long-term debt face amount

$ 750

Long-term debt interest rate

3.90%

Williams Partners L.P. [Member] | 4.9% Senior Unsecured Notes due 2045 [Member]

Debt Instrument [Line Items]

Long-term debt face amount

$ 500

Long-term debt interest rate

4.90%

Williams Partners L.P. [Member] | 4.3% Senior Unsecured Notes Due 2024 [Member]

Debt Instrument [Line Items]

Long-term debt face amount

$ 1,000

Long-term debt interest rate

4.30%

Williams Partners L.P. [Member] | 5.4% Senior Unsecured Notes Due 2044 [Member]

Debt Instrument [Line Items]

Long-term debt face amount

$ 500

Long-term debt interest rate

5.40%

Williams Partners L.P. [Member] | 7.85% Senior Unsecured Notes Due 2026 [Member] | Subsequent Event [Member]

Debt Instrument [Line Items]

Long-term debt interest rate

7.85%

Williams Partners L.P. [Member] | Variable interest Rate [Member]

Debt Instrument [Line Items]

Long-term debt

$ 850

0

Williams Partners L.P. [Member] | 3.8% Senior Unsecured Notes due 2015 [Member]

Debt Instrument [Line Items]

Long-term debt

[1]

$ 0

750

Long-term debt interest rate

3.80%

Williams Partners L.P. [Member] | 3.9% Senior Unsecured Notes due 2025 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 750

750

Long-term debt interest rate

3.90%

Williams Partners L.P. [Member] | 4.9% Senior Unsecured Notes due 2045 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 500

500

Long-term debt interest rate

4.90%

Williams Partners L.P. [Member] | 4.3% Senior Unsecured Notes Due 2024 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 1,000

1,000

Long-term debt interest rate

4.30%

Williams Partners L.P. [Member] | 5.4% Senior Unsecured Notes Due 2044 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 500

500

Long-term debt interest rate

5.40%

Williams Partners L.P. [Member] | 4.5% Senior Unsecured Notes due 2023 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 600

600

Long-term debt interest rate

4.50%

Williams Partners L.P. [Member] | 5.8% Senior Unsecured Notes due 2043 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 400

400

Long-term debt interest rate

5.80%

Williams Partners L.P. [Member] | 5.875% Senior Unsecured Notes due 2021 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 0

750

Long-term debt retired

$ 750

Long-term debt interest rate

5.875%

5.875%

Long-term Debt, Current Maturities

$ 797

Repayments of Long-term Debt

$ 783

Williams Partners L.P. [Member] | 3.6% Senior Unsecured Notes due 2022 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 1,250

0

Long-term debt face amount

$ 1,250

Long-term debt interest rate

3.60%

3.60%

Williams Partners L.P. [Member] | 4% Senior Unsecured Notes due 2025 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 750

0

Long-term debt face amount

$ 750

Long-term debt interest rate

4.00%

4.00%

Williams Partners L.P. [Member] | 5.1% Senior Unsecured Notes due 2045 [Member]

Debt Instrument [Line Items]

Long-term debt

$ 1,000

$ 0

Long-term debt face amount

$ 1,000

Long-term debt interest rate

5.10%

5.10%

[1]

Presented as long-term debt at December 31, 2014, due to WPZ's intent and ability to refinance.

Credit Facilities and Commercia

Credit Facilities and Commercial Paper (Details) $ in Millions		Dec. 18, 2015	Aug. 26, 2015USD ($)	Feb. 02, 2015USD ($)	Dec. 31, 2015USD ($)		Feb. 25, 2016USD ($)	Dec. 23, 2015USD ($)	Mar. 03, 2015USD ($)	Dec. 31, 2014USD ($)
Credit Facility and Commercial Paper [Line Items]
Commercial paper, outstanding					$ 499					$ 798
Williams Companies, Inc. [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				$ 1,500	1,500
Credit facility, loans outstanding					650					370
Additional amount by which credit facility can be increased				$ 500
Maximum ratio of debt to EBITDA				5
Maximum ratio of debt to EBITDA after acquisition				5.5
Williams Companies, Inc. [Member] | Subsequent Event [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, loans outstanding							$ 475
Williams Companies, Inc. [Member] | Swingline Loan [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				$ 50
Williams Companies, Inc. [Member] | Letters of credit [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				675
Williams Companies, Inc. [Member] | Letters Of Credit Under Certain Bilateral Bank Agreements [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, letters of credit outstanding					14
Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				3,500	3,500	[1]
Credit facility, loans outstanding	[1]				1,310
Additional amount by which credit facility can be increased				$ 500
Williams Partners L.P. [Member] | Subsequent Event [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, loans outstanding							$ 925
Williams Partners L.P. [Member] | Rate addition to federal funds effective rate [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, basis spread on variable rate				0.50%
Williams Partners L.P. [Member] | Rate addition to London interbank offered rate (LIBOR) [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, basis spread on variable rate				1.00%
Williams Partners L.P. [Member] | Swingline Loan [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				$ 150
Williams Partners L.P. [Member] | Commercial paper [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				3,000
Commercial paper, outstanding					$ 499					$ 798
Commercial paper, weighted average interest rate					0.92%					0.92%
Commercial paper, maximum maturity					397 days
Williams Partners L.P. [Member] | Letters of credit [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				1,125
Williams Partners L.P. [Member] | Letters Of Credit Under Certain Bilateral Bank Agreements [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, letters of credit outstanding					$ 2
Williams Partners L.P. [Member] | Short-term facility [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity					150
Credit facility, loans outstanding					0
Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity			$ 3,500
Credit facility, loans outstanding					$ 1,310					$ 640
Maximum ratio of debt to EBITDA			6
Williams Partners L.P. [Member] | Short-term facility [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity			$ 1,000					$ 150	$ 1,500
Transcontinental Gas Pipe Line Company, LLC [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				$ 500
Maximum ratio of debt to capitalization				65.00%
Northwest Pipeline LLC [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity				$ 500
Maximum ratio of debt to capitalization				65.00%
Acquisition [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Maximum ratio of debt to EBITDA		5.5
Mar 2017 & Subsequent Quarters [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Maximum ratio of debt to EBITDA		5
Sep & Dec 2016 [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Maximum ratio of debt to EBITDA		5.50
Dec 2015, Mar & Jun 2016 [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Maximum ratio of debt to EBITDA		5.75
Variable Interest Term Loan due 2018 [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Debt Instrument, Interest Rate, Stated Percentage					1.8531%
Long-term debt								$ 850
Variable Interest Term Loan due 2018 [Member] | Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Long-term debt					$ 850					$ 0
[1]	In managing our available liquidity, we do not expect a maximum outstanding amount in excess of the capacity of our credit facility inclusive of any outstanding amounts under our commercial paper program.

Cash Payments For Interest (Net

Cash Payments For Interest (Net of Amounts Capitalized) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Disclosure [Abstract]
Cash payments for interest (net of amounts capitalized)	$ 1,023	$ 681	$ 472

Restricted Net Assets of Subsid

Restricted Net Assets of Subsidiaries (Details) $ in Billions	Dec. 31, 2015USD ($)
Debt Disclosure [Abstract]
Amount of restricted net assets for consolidated and unconsolidated subsidiaries	$ 14
Restricted net assets threshold	25.00%

Leases-Lessee (Details)

Leases-Lessee (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Future minimum annual rentals under noncancelable operating leases
2,016	$ 86
2,017	74
2,018	56
2,019	45
2,020	39
Thereafter	119
Total	419
Operating leases [Abstract]
Total rent expense	$ 164	$ 109	$ 58

Debt, Banking Arrangements, a82

Debt, Banking Arrangements, and Leases Accounting Standards issued and adopted (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Accounting Standards issued and adopted [Abstract]
Debt issuance costs	$ 123	$ 108

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	Jun. 23, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stockholders' Equity (Textuals) [Abstract]
Common Stock, Dividends, Per Share, Declared		$ 2.45	$ 1.9575	$ 1.4375
Stock Issued During Period, Shares, New Issues	61
Equity Issuance, Per Share Amount	$ 57
Common Units Sold In Offering	8
Proceeds from Issuance of Common Stock	$ 3,378	$ 27	$ 3,416	$ 18
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Beginning Balance		(341)
Other comprehensive income (loss)		(171)	(176)	198
Total, Ending Balance		(442)	(341)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Beginning Balance		(341)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		(123)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		22
Other comprehensive income (loss)		(101)	(157)	$ 198
Total, Ending Balance		(442)	(341)
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Beginning Balance		(1)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		3
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		(3)
Other comprehensive income (loss)		0
Total, Ending Balance		(1)	(1)
Foreign currency translation [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Beginning Balance		31
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		(134)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0
Other comprehensive income (loss)		(134)
Total, Ending Balance		(103)	31
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Total, Beginning Balance		(371)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		8
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		25
Other comprehensive income (loss)		33
Total, Ending Balance		$ (338)	$ (371)

Stockholders' Equity Stockholde

Stockholders' Equity Stockholders' Equity Reclassifications from AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Product Sales	$ 2,196	$ 3,521	$ 3,921
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(1,713)	3,584	1,080
Provision (benefit) for income taxes	(399)	$ 1,249	$ 401
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(3)
Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	25
Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	37
Provision (benefit) for income taxes	(15)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	22
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	(3)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), before Tax	(6)
Amortization of actuarial (gain) loss included in net periodic benefit cost	46
Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest	40
Reclassification out of Accumulated Other Comprehensive Income [Member] | Energy Commodity Contract [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Product Sales	$ (3)

Equity-Based Compensation (Deta

Equity-Based Compensation (Details) - USD ($)		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013	May. 22, 2014	May. 20, 2010	May. 17, 2007
Williams Companies Incentive Plan [Member]
Equity-Based Compensation (Textuals) [Abstract]
Shares reserved for issuance		28,000,000				10,000,000	11,000,000	19,000,000
Shares available for future grants		19,000,000
Equity-based compensation expense		$ 56,000,000		$ 44,000,000	$ 37,000,000
Tax benefit from equity-based compensation expense		21,000,000		$ 17,000,000	14,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Abstract]
Unrecognized equity-based compensation expense		65,000,000
Estimated forfeitures under employee equity-based awards		$ 2,000,000
Unrecognized equity-based compensation expense, Weighted-average period of recognition in years		1 year 11 months
Williams Companies Incentive Plan [Member] | Stock options [Member]
Equity-Based Compensation (Textuals) [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period		10 years
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Abstract]
Unrecognized equity-based compensation expense - Stock Options		$ 4,000,000
Rollforward of stock option activity and related information
Options Outstanding, Beginning Balance		5,800,000
Options, Granted		1,000,000
Options, Exercised		(1,100,000)
Options Outstanding, Ending Balance		5,700,000		5,800,000
Options Exercisable at Period End		4,000,000
Options, Aggregate Intrinsic Value, Ending Balance		$ 15,000,000
Options, Aggregate Intrinsic Value, Exercisable at Period End		15,000,000
Total intrinsic value of stock options exercised		37,000,000		$ 48,000,000	23,000,000
Tax benefit realized from stock options exercised		13,000,000		18,000,000	9,000,000
Cash received from stock option exercised		$ 20,000,000		$ 31,000,000	$ 13,000,000
Stock Options Outstanding, Weighted Average Remaining Contractual Life		5 years 8 months
Stock Options Exercisable, Weighted Average Remaining Contractual Life		4 years 5 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Options, Weighted Average Exercise Price, Beginning Balance		$ 25.86
Options, Weighted Average Exercise Price, Granted		49.15
Options, Weighted Average Exercise Price, Exercised		19.30
Options, Weighted Average Exercise Price, Ending Balance		31.51		$ 25.86
Options, Weighted Average Exercise Price, Exercisable at Period End		25.52
Estimated fair value at date of grant of options for common stock granted
Weighted-average grant date fair value of options for our common stock granted during the year, per share		$ 7.61		$ 7.50	$ 5.94
Weighted-average assumptions:
Dividend yield		4.80%		4.20%	4.30%
Volatility		27.80%		28.00%	29.70%
Risk-free interest rate		1.80%		2.20%	1.40%
Expected life (years)		6 years		6 years 6 months	6 years 6 months
Duration Of Base Term For Peer Group Historical Volatility Measurement		10 years
Williams Companies Incentive Plan [Member] | Nonvested Restricted Stock Units [Member]
Equity-Based Compensation (Textuals) [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		3 years
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Abstract]
Unrecognized equity-based compensation expense - Restricted Stock Units		$ 61,000,000
Rollforward of nonvested restricted stock unit activity and related information
Restricted Stock Units, Nonvested shares, Beginning Balance		3,600,000
Restricted Stock Units, Granted		1,400,000
Restricted Stock Units, Forfeited		(100,000)
Restricted Stock Units, Vested, Shares		(1,500,000)
Restricted Stock Units, Nonvested shares, Ending Balance		3,400,000		3,600,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted Stock Units, Nonvested, Weighted-Average Fair Value, Beginning Balance	[1]	$ 33.90
Weighted-average grant date fair value of restricted stock units granted during the year, per share		40.15	[1]	$ 42.79	$ 30.43
Restricted Stock Units, Forfeited, Weighted-Average Fair Value	[1]	36.49
Restricted Stock Units, Vested, Weighted-Average Fair Value	[1]	27.45
Restricted Stock Units, Nonvested, Weighted-Average Fair Value, Ending Balance	[1]	$ 39.38		$ 33.90
Restricted Stock Units, Vested in Period, Fair Value		$ 42,000,000		$ 27,000,000	$ 27,000,000
Williams Companies Incentive Plan [Member] | Performance Shares [Member]
Equity-Based Compensation (Textuals) [Abstract]
Share Based Compensation Arrangement By Share Based Payment Award Duration Of Postvesting Restriction On Sale		2 years
Rollforward of nonvested restricted stock unit activity and related information
Performance based nonvested restricted stock units as a percent of total nonvested restricted stock units outstanding		40.00%
Williams Companies Incentive Plan [Member] | Performance Shares [Member] | Minimum [Member]
Rollforward of nonvested restricted stock unit activity and related information
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Discount for Postvesting Restrictions		5.83%
Range of vested shares based on extent to which certain financial targets are achieved		0.00%
Williams Companies Incentive Plan [Member] | Performance Shares [Member] | Maximum [Member]
Rollforward of nonvested restricted stock unit activity and related information
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Discount for Postvesting Restrictions		15.58%
Range of vested shares based on extent to which certain financial targets are achieved		500.00%
Employee Stock Purchase Plan [Member]
Equity-Based Compensation (Textuals) [Abstract]
Shares reserved for issuance						1,600,000		2,000,000
Shares available for future grants		1,500,000
Maximum annual amount for purchase of common stock per participant under employee stock purchase plan		$ 15,000
Number of shares eligible for employee to purchase per offering period		750
Percentage of purchase price is the lower of closing price of either the first or the last day of the offering period		85.00%
No. of shares purchases by employees		354,000
Average price of shares purchased		$ 28.07
Share Based Compensation Arrangement By Share Based Payment Award Duration Of Postvesting Restriction On Sale		1 year
Williams Partners Long Term Incentive Plan [Member] | Nonvested Restricted Stock Units [Member]
Equity-Based Compensation (Textuals) [Abstract]
Equity-based compensation expense		$ 29,000,000		$ 11,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Abstract]
Unrecognized equity-based compensation expense - Restricted Stock Units		32,000,000
Estimated forfeitures under employee equity-based awards		$ 4,000,000
Unrecognized equity-based compensation expense, Weighted-average period of recognition in years		1 year 10 months
Rollforward of nonvested restricted stock unit activity and related information
Restricted Stock Units, Nonvested shares, Beginning Balance		1,300,000
Restricted Stock Units, Granted		0
Restricted Stock Units, Adjustment for unit split in ACMP Merger		100,000
Restricted Stock Units, Forfeited		(100,000)
Restricted Stock Units, Vested, Shares		(100,000)
Restricted Stock Units, Nonvested shares, Ending Balance		1,200,000		1,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted Stock Units, Nonvested, Weighted-Average Fair Value, Beginning Balance		$ 59.35
Restricted Stock Units, Adjustment for unit split in ACMP Merger, Weighted-Average Fair Value		0
Restricted Stock Units, Forfeited, Weighted-Average Fair Value		58.05
Restricted Stock Units, Vested, Weighted-Average Fair Value		59.28
Restricted Stock Units, Nonvested, Weighted-Average Fair Value, Ending Balance		$ 55.93		$ 59.35
Williams Partners Long Term Incentive Plan [Member] | Nonvested Restricted Stock Units [Member] | Minimum [Member]
Equity-Based Compensation (Textuals) [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		1 year
Williams Partners Long Term Incentive Plan [Member] | Nonvested Restricted Stock Units [Member] | Maximum [Member]
Equity-Based Compensation (Textuals) [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years
[1]	Performance-based restricted stock units are valued utilizing a Monte Carlo valuation method using measures of total shareholder return. Certain of the performance-based restricted stock units are subject to a holding period of up to two years after the vesting date. Discounts for the restrictions of liquidity were applied to the estimated fair value at the date of the awards and ranged from 5.83 percent to 15.58 percent. The discounts were developed using the Chaffe model and the Finnerty model. All other restricted stock units are valued at the grant-date market price. Restricted stock units generally vest after three years.

Fair Value Measurements Recurri

Fair Value Measurements Recurring Measurements and Additional (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Measured on a recurring basis:
Unamortized debt issuance expense		$ 123	$ 108
Additional disclosure:
Fair Value, Level 1 to level 2 Transfers, Amount		0	0
Fair Value, Level 2 to level 1 Transfers, Amount		0	0
Former Venezuela Operations [Member]
Additional disclosure:
Cash Installments Related To Former Operations Settlement		15
Level 1 [Member]
Additional disclosure:
Notes receivable and other		10	0
Long-term debt, including current portion	[1]	0	0
Guarantee		0	0
Level 2 [Member]
Additional disclosure:
Notes receivable and other		2	4
Long-term debt, including current portion	[1]	(19,606)	(21,131)
Guarantee		(16)	(27)
Level 3 [Member]
Additional disclosure:
Notes receivable and other		18	53
Long-term debt, including current portion	[1]	0	0
Guarantee		0	0
Carrying Amount [Member]
Additional disclosure:
Notes receivable and other		12	30
Long-term debt, including current portion	[1]	(23,987)	(20,779)
Guarantee		(29)	(31)
Carrying Amount [Member] | Former Venezuela Operations [Member]
Additional disclosure:
Notes Receivable, Fair Value Disclosure		0
Fair Value [Member]
Additional disclosure:
Notes receivable and other		30	57
Long-term debt, including current portion	[1]	(19,606)	(21,131)
Guarantee		(16)	(27)
Fair Value [Member] | Former Venezuela Operations [Member]
Additional disclosure:
Notes Receivable, Fair Value Disclosure		18
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Measured on a recurring basis:
ARO Trust investments		67	48
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis:
Energy derivatives assets		0	1
Energy derivative liabilities		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Measured on a recurring basis:
ARO Trust investments		0	0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis:
Energy derivatives assets		3	0
Energy derivative liabilities		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Measured on a recurring basis:
ARO Trust investments		0	0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis:
Energy derivatives assets		2	2
Energy derivative liabilities		(2)	(2)
Fair Value, Measurements, Recurring [Member] | Carrying Amount [Member]
Measured on a recurring basis:
ARO Trust investments		67	48
Fair Value, Measurements, Recurring [Member] | Carrying Amount [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis:
Energy derivatives assets		5	3
Energy derivative liabilities		(2)	(2)
Fair Value, Measurements, Recurring [Member] | Fair Value [Member]
Measured on a recurring basis:
ARO Trust investments		67	48
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis:
Energy derivatives assets		5	3
Energy derivative liabilities		$ (2)	$ (2)
[1]	Excludes capital leases. The carrying value has been reduced by $123 million and $108 million of debt acquisition costs at December 31, 2015 and 2014, respectively. (See Note 14 – Debt, Banking Arrangements, and Leases.)

Fair Value Measurements Nonrecu

Fair Value Measurements Nonrecurring Measurements (Details) - USD ($) $ in Millions

3 Months Ended

9 Months Ended

12 Months Ended

Dec. 31, 2015

Sep. 30, 2015

Jun. 30, 2015

[3]

Dec. 31, 2014

Jun. 30, 2014

[3]

Sep. 30, 2015

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Impairment of goodwill

$ 1,098

$ 1,098

$ 0

$ 0

Impairment of equity-method investments

1,359

0

$ 0

Williams Partners [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Impairment of goodwill

1,098

Property, plant, and equipment, net [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Impairment of certain assets

209

52

Fair Value, Measurements, Nonrecurring [Member] | Property, plant, and equipment, net [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Impairment of certain assets

[1]

31

10

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Goodwill [Member] | Williams Partners [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Impairment of goodwill

$ 1,098

$ 0

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Goodwill [Member] | Williams Partners [Member] | Minimum [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Discount rate

10.00%

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Goodwill [Member] | Williams Partners [Member] | Maximum [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Discount rate

13.00%

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Goodwill [Member] | West [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Impairment of goodwill

$ 0

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Property, plant, and equipment, net [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Impairment of certain assets

178

42

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Property, plant, and equipment, net [Member] | Williams Partners [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Fair value of property, plant, and equipment

13

[2]

$ 17

$ 32

[3]

$ 46

13

[2]

32

[3]

Assets Held-for-sale, Long Lived, Fair Value Disclosure

[4]

1

$ 1

Impairment of certain assets

94

[2]

$ 20

13

[3]

$ 17

Impairment of Long-Lived Assets to be Disposed of

[4]

$ 12

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Property, plant, and equipment, net [Member] | Williams Ngl And Petchem Services [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Fair value of property, plant, and equipment

[5]

40

40

Impairment of certain assets

[5]

64

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member] | Williams Partners [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Fair value of investment

4,017

[6]

$ 1,203

[7]

$ 1,203

[7]

4,017

[6]

Impairment of equity-method investments

$ 890

[6]

$ 461

[7]

1,359

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member] | Williams Partners [Member] | Minimum [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Discount rate

10.80%

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member] | Williams Partners [Member] | Maximum [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Discount rate

14.40%

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member] | Williams Partners [Member] | Delaware Basin Gas Gathering System [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Discount rate

11.80%

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member] | Williams Partners [Member] | Appalachia Midstream Investments [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Discount rate

8.80%

Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member] | Investments [Member] | Williams Partners [Member] | Other Investments [Member]

Fair Value Assets Measured On Nonrecurring Basis [Abstract]

Fair value of investment

$ 58

$ 58

Impairment of equity-method investments

$ 8

[1]

Reflects multiple individually insignificant impairments of other certain assets that may no longer be in use or are surplus in nature for which the fair value was determined to be zero or an insignificant salvage value. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations

[2]

Reflects an impairment charge within our Williams Partners segment associated with previously capitalized project development costs for a gas processing plant, the completion of which is now considered remote due to unfavorable impact of low natural gas prices on customer drilling activities. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations.The assessed fair value primarily represents the estimated salvage value of certain equipment measured using a market approach based on our analysis of observable inputs in the principal market and is reported in Property, plant, and equipment – net in the Consolidated Balance Sheet.

[3]

Reflects impairment charges for our Williams Partners segment associated with certain surplus equipment. Certain of these assets were previously presented as held for sale, but are now considered held for use and reported in Property, plant, and equipment – net in the Consolidated Balance Sheet at December 31, 2015. The estimated fair value was determined by a market approach based on our analysis of observable inputs in the principal market. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations.

[4]

Reflects impairment charges for our Williams Partners segment associated with certain surplus equipment considered held for sale and reported in Other current assets and deferred charges in the Consolidated Balance Sheet. The estimated fair value was determined by a market approach based on our analysis of observable inputs in the principal market. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations.

[5]

Reflects an impairment charge within our Williams NGL & Petchem Services segment associated with previously capitalized project development costs for an olefins pipeline project, the completion of which is now considered remote due to the lack of customer interest. These impairment charges are recorded in Other (income) expense – net within Costs and expenses in the Consolidated Statement of Operations. The assessed fair value primarily represents the estimated value of unused pipeline measured using a market approach based on our analysis of observable inputs in the principal market and is reported in Property, plant, and equipment – net in the Consolidated Balance Sheet.

[6]

Reflects other-than-temporary impairment charges related to Williams Partners’ equity-method investments in the Delaware basin gas gathering system, certain of the Appalachia Midstream Investments, UEOM, and Laurel Mountain, reflected within Impairment of equity-method investments in the Consolidated Statement of Operations. We estimated the fair value of these investments using an income approach based on expected future cash flows and appropriate discount rates. The determination of estimated future cash flows involved significant assumptions regarding gathering volumes and related capital spending. Discount rates utilized ranged from 10.8 percent to 14.4 percent and reflected further fourth quarter increases in our cost of capital, revised estimates of expected future cash flows, and risks associated with the underlying businesses.

[7]

Reflects other-than-temporary impairment charges related to Williams Partners’ equity-method investments in the Delaware basin gas gathering system and certain of the Appalachia Midstream Investments reflected within Impairment of equity-method investments in the Consolidated Statement of Operations. The historical carrying value of these investments was initially recorded based on estimated fair value during the third quarter of 2014 in conjunction with the ACMP Acquisition. We estimated the fair value of these investments using an income approach based on expected future cash flows and appropriate discount rates. The determination of estimated future cash flows involved significant assumptions regarding gathering volumes and related capital spending. Discount rates utilized were 11.8 percent and 8.8 percent for the Delaware basin gas gathering system and certain of the Appalachia Midstream Investments, respectively, and reflected our cost of capital as impacted by market conditions, and risks associated with the underlying businesses.

Fair Value Measurements (Detail

Fair Value Measurements (Details Guarantees and Credit Risk) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Concentration Risk [Line Items]
Receivables by product or service	$ 1,041	$ 1,139
Customer Concentration Risk [Member] | Accounts receivable [Member] | Chesapeake Energy Corporation [Member] | Williams Partners [Member]
Concentration Risk [Line Items]
Receivables by product or service	$ 364	$ 308
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Chesapeake Energy Corporation [Member] | Williams Partners [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	18.00%	9.00%
NGLs, natural gas, and related products and services [Member]
Concentration Risk [Line Items]
Receivables by product or service	$ 823	$ 730
Transportation of natural gas and related products [Member]
Concentration Risk [Line Items]
Receivables by product or service	202	175
Income tax receivable [Member]
Concentration Risk [Line Items]
Receivables by product or service	7	167
Other Receivable [Member]
Concentration Risk [Line Items]
Receivables by product or service	9	$ 67
Minimum Volume Commitment [Member] | Customer Concentration Risk [Member] | Chesapeake Energy Corporation [Member] | Williams Partners [Member]
Concentration Risk [Line Items]
Receivables by product or service	198
Wiltel Guarantee [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	$ 33

Contingent Liabilities and Co89

Contingent Liabilities and Commitments (Details) $ in Millions	Dec. 31, 2015USD ($)
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities	$ 40
Capital Addition Purchase Commitments [Member]
Loss Contingencies [Line Items]
Commitments for construction and acquisition of property, plant and equipment	770
Former Alaska Refinery [Member]
Loss Contingencies [Line Items]
Loss Contingency, Range of Possible Loss, Maximum	32
Gas Pipeline [Member]
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities	8
Natural gas underground storage facilities [Member]
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities	7
Former Operations [Member]
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities	25
Williams Partners [Member] | General Liability [Member] | Geismar Incident [Member]
Loss Contingencies [Line Items]
Aggregate Annual Limit of Insurance	610
Insurance Deductibles	$ 2

Segment Disclosures Geographic

Segment Disclosures Geographic Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues from external customers:
Revenues from external customers	$ 7,360	$ 7,637	$ 6,860
Long-lived assets:
Long-lived assets	39,596	39,654	20,500
United States [Member]
Revenues from external customers:
Revenues from external customers	7,247	7,229	6,703
Long-lived assets:
Long-lived assets	38,016	38,290	19,260
Canada [Member]
Revenues from external customers:
Revenues from external customers	113	408	157
Long-lived assets:
Long-lived assets	$ 1,580	$ 1,364	$ 1,240

Segment Disclosures Recon from

Segment Disclosures Recon from Segment to Consolidated - Revenues (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		$ 7,360	$ 7,637		$ 6,860
Other financial information:
Additions to long-lived assets		3,336	20,756		3,731
Proportional Modified Ebitda Equity Method Investments		699	438		406
Service [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		5,164	4,116		2,939
Service [Member] | Williams Partners [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		5,134	3,887		2,914
Service [Member] | Williams Ngl And Petchem Services [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	[1]	2	0		0
Service [Member] | Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		28	229		25
Product [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		2,196	3,521		3,921
Product [Member] | Williams Partners [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		2,196	3,521		3,921
Product [Member] | Williams Ngl And Petchem Services [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	[1]	0	0		0
Product [Member] | Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		0	0		0
Operating Segments [Member] | Williams Partners [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		7,331	7,409		6,835
Other financial information:
Additions to long-lived assets		2,960	20,413	[2]	3,409
Proportional Modified Ebitda Equity Method Investments		699	431		209
Operating Segments [Member] | Williams Ngl And Petchem Services [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	[1]	2	0		0
Other financial information:
Additions to long-lived assets		360	291		295
Proportional Modified Ebitda Equity Method Investments		0	(78)		0
Operating Segments [Member] | Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		186	259		36
Other financial information:
Additions to long-lived assets		28	54		27
Proportional Modified Ebitda Equity Method Investments		0	85		197
Operating Segments [Member] | Service [Member] | Williams Partners [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		5,135	3,888		2,914
Operating Segments [Member] | Service [Member] | Williams Ngl And Petchem Services [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	[1]	2	0		0
Operating Segments [Member] | Service [Member] | Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		186	259		36
Operating Segments [Member] | Product [Member] | Williams Partners [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		2,196	3,521		3,921
Operating Segments [Member] | Product [Member] | Williams Ngl And Petchem Services [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	[1]	0	0		0
Operating Segments [Member] | Product [Member] | Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		0	0		0
Intersegment Eliminations [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		(159)	(31)		(11)
Other financial information:
Additions to long-lived assets		(12)	(2)		0
Intersegment Eliminations [Member] | Service [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		(159)	(31)		(11)
Intersegment Eliminations [Member] | Service [Member] | Williams Partners [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		(1)	(1)		0
Intersegment Eliminations [Member] | Service [Member] | Williams Ngl And Petchem Services [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	[1]	0	0		0
Intersegment Eliminations [Member] | Service [Member] | Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		(158)	(30)		(11)
Intersegment Eliminations [Member] | Product [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		0	0		0
Intersegment Eliminations [Member] | Product [Member] | Williams Partners [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		0	0		0
Intersegment Eliminations [Member] | Product [Member] | Williams Ngl And Petchem Services [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	[1]	0	0		0
Intersegment Eliminations [Member] | Product [Member] | Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		$ 0	$ 0		$ 0
[1]	Includes certain projects under development and thus nominal reported revenues to date.
[2]	2014 Additions to long-lived assets within our Williams Partners segment primarily includes the acquisition-date fair value of long-lived assets from the ACMP Acquisition. (See Note 2 - Acquisitions.)

Segment Disclosures Recon fro92

Segment Disclosures Recon from Segment to Consolidated - Modified EBITDA (Details 1) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Modified EBITDA by segment to Net Income Loss
Modified Ebitda		$ 3,891	$ 3,232	$ 2,611
Asset Retirement Obligation Accretion Expense For Nonregulated Operations		(28)	(18)	(15)
Depreciation and amortization expenses		(1,738)	(1,176)	(815)
Impairment of goodwill	$ (1,098)	(1,098)	0	0
Equity earnings (losses)		335	144	134
Gain on remeasurement of equity-method investment		0	2,544	0
Impairment of equity-method investments		(1,359)	0	0
Other investing income (loss) – net		27	43	81
Proportional Modified Ebitda Equity Method Investments		(699)	(438)	(406)
Interest Expense		(1,044)	(747)	(510)
(Provision) benefit for income taxes		399	(1,249)	(401)
Income (loss) from discontinued operations, net of tax		0	4	(11)
Net income (loss)		(1,314)	2,339	668
Williams Partners [Member]
Reconciliation of Modified EBITDA by segment to Net Income Loss
Impairment of goodwill		(1,098)
Operating Segments [Member] | Williams Partners [Member]
Reconciliation of Modified EBITDA by segment to Net Income Loss
Modified Ebitda		4,003	3,244	2,447
Proportional Modified Ebitda Equity Method Investments		(699)	(431)	(209)
Operating Segments [Member] | Williams NGL & Petchem Services [Member]
Reconciliation of Modified EBITDA by segment to Net Income Loss
Modified Ebitda		(83)	(115)	(33)
Proportional Modified Ebitda Equity Method Investments		0	78	0
Operating Segments [Member] | Other [Member]
Reconciliation of Modified EBITDA by segment to Net Income Loss
Modified Ebitda		(29)	103	197
Proportional Modified Ebitda Equity Method Investments		$ 0	$ (85)	$ (197)

Segment Disclosures Recon fro93

Segment Disclosures Recon from Segment to Consolidated - Assets and Investments (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	$ 49,020	$ 50,455
Equity Method Investments	7,336	8,400
Operating Segments [Member] | Williams Partners [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	47,870	49,248
Equity Method Investments	7,336	8,399
Operating Segments [Member] | Williams Ngl And Petchem Services [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	835	612
Equity Method Investments	0	0
Operating Segments [Member] | Other [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	850	1,186
Equity Method Investments	0	1
Intersegment Eliminations [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Total assets	(535)	(591)
Equity Method Investments	$ 0	$ 0

Schedule I Condensed Financia94

Schedule I Condensed Financial Information Of Registrant (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	Jun. 23, 2014	Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014
Condensed Statement Of Comprehensive Income Parent Company Only [Abstract]
Equity earnings (losses)		$ 335		$ 144	$ 134
Interest incurred - external		(1,118)		(888)	(611)
Gain on remeasurement of equity-method investment		0		2,544	0
Other income (expense) – net		102		31	0
Income (loss) from continuing operations before income taxes		(1,713)		3,584	1,080
Provision (benefit) for income taxes		(399)		1,249	401
Income (loss) from continuing operations		(571)		2,110	441
Income (loss) from discontinued operations		0		4	(11)
Net income (loss) attributable to The Williams Companies, Inc.		$ (571)		$ 2,114	$ 430
Basic earnings (loss) per common share:
Income (loss) from continuing operations		$ (0.76)		$ 2.93	$ 0.65
Income (loss) from discontinued operations		0		0.01	(0.02)
Net income (loss)		$ (0.76)		$ 2.94	$ 0.63
Weighted-average shares (thousands)		749,271		719,325	682,948
Diluted earnings (loss) per common share:
Income (loss) from continuing operations		$ (0.76)		$ 2.91	$ 0.64
Income (loss) from discontinued operations		0		0.01	(0.02)
Net income (loss)		$ (0.76)		$ 2.92	$ 0.62
Weighted-average shares (thousands)		749,271	[1]	723,641	687,185
Other comprehensive income (loss):
Other comprehensive income (loss)		$ (171)		$ (176)	$ 198
Comprehensive Income (loss) attributable to The Williams Companies, Inc.		(672)		1,957	628
Assets, Current [Abstract]
Cash and cash equivalents		240		681	839	$ 100	$ 240
Other current assets and deferred charges						217	213
Total current assets						1,527	1,890
Property, plant, and equipment – net						29,579	28,081
Other noncurrent assets						561	511
Total assets						49,020	50,455
Liabilities, Current [Abstract]
Accounts payable						744	865
Total current liabilities						2,497	2,567
Long-term debt						23,812	20,780
Deferred income taxes						$ 4,218	$ 4,712
Contingent liabilities and commitments
Equity: [Abstract]
Common stock						$ 784	$ 782
Total stockholders’ equity						6,148	8,777
Total liabilities and stockholders' equity						49,020	50,455
Condensed Statement Of Cash Flows Parent Company Only [Abstract]
Net Cash Provided (Used) by Operating Activities		2,678		2,115	2,217
FINANCING ACTIVITIES:
Proceeds from long-term debt		9,772		7,321	2,699
Payments of long-term debt		(6,516)		(1,828)	(2,081)
Proceeds from issuance of common stock	$ 3,378	27		3,416	18
Dividends paid		(1,836)		(1,412)	(982)
Other – net		(1)		17	17
Net cash provided (used) by financing activities		481		7,601	1,677
INVESTING ACTIVITIES:
Capital expenditures		(3,336)		(20,756)	(3,731)
Other – net		572		280	(22)
Net cash provided (used) by investing activities		(3,299)		(10,157)	(4,052)
Increase (decrease) in cash and cash equivalents		(140)		(441)	(158)
Cash and cash equivalents at beginning of year		240		681	839
Cash and cash equivalents at end of year		100		240	681
Parent Company [Member]
Condensed Statement Of Comprehensive Income Parent Company Only [Abstract]
Equity in earnings of consolidated subsidiaries		232		1,799	1,564
Equity earnings (losses)		0		(7)	30
Interest incurred - external		(255)		(206)	(156)
Interest incurred - affiliate		(828)		(797)	(722)
Interest income - affiliate		6		10	71
Gain on remeasurement of equity-method investment		0		2,544	0
Other income (expense) – net		(75)		(13)	32
Income (loss) from continuing operations before income taxes		(920)		3,330	819
Provision (benefit) for income taxes		(349)		1,220	378
Income (loss) from continuing operations		(571)		2,110	441
Income (loss) from discontinued operations		0		4	(11)
Net income (loss) attributable to The Williams Companies, Inc.		$ (571)		$ 2,114	$ 430
Basic earnings (loss) per common share:
Income (loss) from continuing operations		$ (0.76)		$ 2.93	$ 0.65
Income (loss) from discontinued operations		0		0.01	(0.02)
Net income (loss)		$ (0.76)		$ 2.94	$ 0.63
Weighted-average shares (thousands)		749,271		719,325	682,948
Diluted earnings (loss) per common share:
Income (loss) from continuing operations		$ (0.76)		$ 2.91	$ 0.64
Income (loss) from discontinued operations		0		0.01	(0.02)
Net income (loss)		$ (0.76)		$ 2.92	$ 0.62
Weighted-average shares (thousands)		749,271		723,641	687,185
Other comprehensive income (loss):
Equity in other comprehensive income (loss) of consolidated subsidiaries		$ (204)		$ (96)	$ (41)
Other comprehensive income (loss) attributable to The Williams Companies, Inc.		33		(80)	239
Other comprehensive income (loss)		(171)		(176)	198
Other comprehensive income (loss) attributable to noncontrolling interests		(70)		(19)	0
Comprehensive Income (loss) attributable to The Williams Companies, Inc.		(672)		1,957	628
Assets, Current [Abstract]
Cash and cash equivalents		49		282	340	12	49
Other current assets and deferred charges						62	246
Total current assets						74	295
Investments in and advances to consolidated subsidiaries						30,927	31,405
Property, plant, and equipment – net						99	99
Other noncurrent assets						12	12
Total assets						31,112	31,811
Liabilities, Current [Abstract]
Accounts payable						27	27
Other current liabilities						163	174
Total current liabilities						190	201
Long-term debt						4,811	4,528
Notes payable - affiliates						15,506	13,295
Pension, other postretirement and other noncurrent liabilities						336	409
Deferred income taxes						$ 4,121	$ 4,601
Contingent liabilities and commitments
Equity: [Abstract]
Common stock						$ 784	$ 782
Other stockholders' equity						5,364	7,995
Total stockholders’ equity						6,148	8,777
Total liabilities and stockholders' equity						31,112	$ 31,811
Condensed Statement Of Cash Flows Parent Company Only [Abstract]
Net Cash Provided (Used) by Operating Activities		(1,209)		(500)	19
FINANCING ACTIVITIES:
Proceeds from long-term debt		2,097		2,935	0
Payments of long-term debt		(1,817)		(671)	(1)
Changes in notes payable to affiliates		2,211		2,465	1,892
Tax benefit of stock-based awards		0		25	19
Proceeds from issuance of common stock		27		3,416	18
Dividends paid		(1,836)		(1,412)	(982)
Other – net		(2)		(17)	(3)
Net cash provided (used) by financing activities		680		6,741	943
INVESTING ACTIVITIES:
Capital expenditures		(29)		(54)	(23)
Purchase of Access Midstream Partners		0		(5,995)	0
Changes in investments in and advances to consolidated subsidiaries		521		(450)	(985)
Other – net		0		25	(12)
Net cash provided (used) by investing activities		492		(6,474)	(1,020)
Increase (decrease) in cash and cash equivalents		(37)		(233)	(58)
Cash and cash equivalents at beginning of year		49		282	340
Cash and cash equivalents at end of year		12		49	282
Guarantees [Abstract]
Guarantor Obligations, Maximum Exposure, Undiscounted						$ 631
Cash Dividends Received [Abstract]
Proceeds from Dividends Received		$ 1,800		$ 1,900	$ 1,500
[1]	For the year ended December 31, 2015, 1.7 million weighted-average nonvested restricted stock units and 1.5 million weighted-average stock options have been excluded from the computation of diluted earnings (loss) per common share as their inclusion would be antidilutive due to our loss from continuing operations attributable to The Williams Companies, Inc.

Schedule II Valuation and Qua95

Schedule II Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for doubtful accounts and for notes receivable [Member]
Valuation And Qualifying Accounts
Beginning Balance	[1]	$ 0	$ 0	$ 0
Additions Charged (Credited) To Cost and Expenses		3	0	0
Additions Other		0	0	0
Deductions		0	0	0
Ending Balance	[1]	3	0	0
Deferred Tax Asset Valuation Allowance [Member]
Valuation And Qualifying Accounts
Beginning Balance	[1]	206	181	144
Additions Charged (Credited) To Cost and Expenses		(16)	25	37
Additions Other		0	0	0
Deductions		0	0	0
Ending Balance	[1]	$ 190	$ 206	$ 181
[1]	Deducted from related assets.