The Williams Companies, Inc. (WMB) 10-K 25 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014	Feb. 23, 2015	Jun. 30, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	Williams Companies Inc
Entity Central Index Key	107263
Document Type	10-K
Document Period End Date	31-Dec-14
Amendment Flag	FALSE
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$22,144,393,171
Entity Common Stock, Shares Outstanding		747,896,477

Consolidated_Statement_of_Inco

Consolidated Statement of Income (USD $)	12 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Revenues:
Service revenues	$4,116		$2,939		$2,729
Product sales	3,521		3,921		4,757
Total revenues	7,637		6,860		7,486
Costs and expenses:
Product costs	3,016		3,027		3,496
Operating and maintenance expenses	1,492		1,097		1,027
Depreciation and amortization expenses	1,176		815		756
Selling, general, and administrative expenses	661		512		571
Net insurance recoveries - Geismar Incident	-232		-40		0
Other (income) expense - net	-45		74		24
Total costs and expenses	6,068		5,485		5,874
Operating income (loss)	1,569		1,375		1,612
Equity earnings (losses)	144	[1]	134	[1]	111	[1]
Gain on remeasurement of equity-method investment	2,544	[1]	0	[1]	0	[1]
Other investing income (loss) - net	43		81		77
Interest incurred	-888		-611		-568
Interest capitalized	141		101		59
Other income (expense) - net	31		0		-2
Income (loss) from continuing operations before income taxes	3,584		1,080		1,289
Provision (benefit) for income taxes	1,249		401		360
Income (loss) from continuing operations	2,335		679		929
Income (loss) from discontinued operations	4		-11		136
Net income (loss)	2,339		668		1,065
Less: Net income attributable to noncontrolling interests	225		238		206
Net income (loss) attributable to The Williams Companies, Inc.	2,114		430		859
Amounts attributable to The Williams Companies, Inc.:
Income (loss) from continuing operations	2,110		441		723
Income (loss) from discontinued operations	4		-11		136
Net income (loss) attributable to The Williams Companies, Inc.	$2,114		$430		$859
Basic earnings (loss) per common share:
Income (loss) from continuing operations	$2.93		$0.65		$1.17
Income (loss) from discontinued operations	$0.01		($0.02)		$0.22
Net income (loss)	$2.94		$0.63		$1.39
Weighted-average shares (thousands)	719,325		682,948		619,792
Diluted earnings (loss) per common share:
Income (loss) from continuing operations	$2.91		$0.64		$1.15
Income (loss) from discontinued operations	$0.01		($0.02)		$0.22
Net income (loss)	$2.92		$0.62		$1.37
Weighted-average shares (thousands)	723,641		687,185		625,486
[1]	Items also included in Segment profit (loss). (See Note 19 – Segment Disclosures.)

Consolidated_Statement_of_Comp

Consolidated Statement of Comprehensive Income (Loss) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Comprehensive income (loss):
Net income (loss)	$2,339	$668	$1,065
Cash flow hedging activities:
Net unrealized gain (loss) from derivative instruments, net of taxes	0	1	22
Reclassifications into earnings of net derivative instruments (gain) loss, net of taxes	0	-1	-23
Foreign currency translation adjustments	-96	-41	22
Pension and other postretirement benefits:
Prior service credit (cost) arising during the year, net of taxes	-1	14	1
Amortization of prior service cost (credit) included in net periodic benefit cost, net of taxes	-5	-2	-1
Net actuarial gain (loss) arising during the year, net of taxes	-100	189	-30
Amortization of actuarial (gain) loss included in net periodic benefit cost, net of taxes	26	38	39
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax	0	0	3
Other comprehensive income (loss)	-176	198	27
Comprehensive income (loss)	2,163	866	1,092
Less: Comprehensive income (loss) attributable to noncontrolling interest	206	238	206
Comprehensive Income (loss) attributable to The Williams Companies, Inc.	$1,957	$628	$886

Consolidated_Statement_of_Comp1

Consolidated Statement of Comprehensive Income (Loss) (Parenthetical) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
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	($7)
Other Comprehensive Income Loss Reclassification Adjustment On Derivatives Included In Net Income Tax	0	0	7
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	18	24	0
Other Comprehensive Income Defined Benefit Plans Tax [Abstract]
Other Comprehensive Income Loss Pension And Other Postretirement Benfit Plans, Benefit Plan Improvement, Tax Effect	0	-9	-1
Other Comprehensive Income Amortization Of Defined Benefit Plan Net Prior Service Cost Recognized In Net Periodic Pension Cost Tax	3	1	1
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax	60	-111	19
Other Comprehensive Income Loss Reclassification Pension And Other Postretirement Benefit Plans Net Gain Loss Recognized In Net Periodic Benefit Cost Tax	-15	-23	-22
Other Comprehensive Income Available For Sale Securities Tax [Abstract]
Other Comprehensive Income Loss Reclassification Adjustment For Sale Of Securities Included In Net Income Tax	$0	$0	$2

Consolidated_Balance_Sheet

Consolidated Balance Sheet (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Current assets:
Cash and cash equivalents	$240	$681
Accounts and notes receivable, net:
Trade and other	972	600
Income tax receivable	167	74
Deferred income tax asset	67	27
Inventories	231	194
Other current assets and deferred charges	213	107
Total current assets	1,890	1,683
Investments	8,400	4,360
Property, plant, and equipment - net	28,081	18,210
Goodwill	1,120	646
Other intangible assets, net of accumulated amortization	10,453	1,644
Regulatory assets, deferred charges, and other	619	599
Total assets	50,563	27,142
Current liabilities:
Accounts payable	865	960
Accrued liabilities	900	797
Commercial paper	798	225
Long-term debt due within one year	4	1
Total current liabilities	2,567	1,983
Long-term debt	20,888	11,353
Deferred income taxes	4,712	3,529
Other noncurrent liabilities	2,224	1,356
Contingent liabilities and commitments (Note 18)
Stockholders' equity:
Common stock (960 million shares authorized at $1 par value; 782 million shares issued at December 31, 2014, and 718 million shares issued at December 31, 2013)	782	718
Capital in excess of par value	14,925	11,599
Retained deficit	-5,548	-6,248
Accumulated other comprehensive income (loss)	-341	-164
Treasury stock, at cost (35 million shares of common stock)	-1,041	-1,041
Total stockholders' equity	8,777	4,864
Noncontrolling interests in consolidated subsidiaries	11,395	4,057
Total equity	20,172	8,921
Total liabilities and equity	$50,563	$27,142

Consolidated_Balance_Sheet_Par

Consolidated Balance Sheet (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, except Per Share data, unless otherwise specified
Stockholders' equity:
Common Stock, Shares Authorized	960	960
Common Stock, Par or Stated Value Per Share	$1	$1
Common Stock, Shares Issued	782	718
Treasury Stock, Shares	35	35

Consolidated_Statement_of_Chan

Consolidated Statement of Changes in Equity (USD $)	Total	Common Stock	Capital in Excess of Par Value	Retained Earnings (Deficit)	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Total Stockholders' Equity	Noncontrolling Interests
In Millions
Beginning balance at Dec. 31, 2011	$2,586	$626	$7,920	($5,820)	($389)	($1,041)	$1,296	$1,290
Net income (loss)	1,065	0	0	859	0	0	859	206
Other comprehensive income (loss)	27	0	0	0	27	0	27	0
Noncontrolling Interest, Increase from Business Combination	1,044	0	0	0	0	0	0	1,044
Cash dividends - common stock (Note 15)	-742	0	0	-742	0	0	-742	0
Dividends and distributions to noncontrolling interests	-387	0	0	0	0	0	0	-387
Issuance of common stock from debentures conversion	6	1	5	0	0	0	6	0
Stock-based compensation and related common stock issuances, net of tax	104	6	98	0	0	0	104	0
Sales of limited partner units of Williams Partners L.P.	1,559	0	0	0	0	0	0	1,559
Changes in Williams Partners L.P. ownership interest, net	-416	0	699	0	0	0	699	-1,115
Sales of common stock	2,495	83	2,412	0	0	0	2,495	0
Reconsolidation of noncontrolling interest in Wilpro entities	65	0	0	0	0	0	0	65
Proceeds from (Payments to) Noncontrolling Interests	14	0	0	0	0	0	0	14
Other	7	0	0	8	0	0	8	-1
Stockholders' Equity, Period Increase (Decrease)	4,841	90	3,214	125	27	0	3,456	1,385
Ending 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
Proceeds from (Payments to) Noncontrolling Interests	467	0	0	0	0	0	0	467
Other	-1	0	1	-1	0	0	0	-1
Stockholders' Equity, Period Increase (Decrease)	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, Increase from Business Combination	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
Sales of common stock	3,378	61	3,317	0	0	0	3,378	0
Proceeds from (Payments to) Noncontrolling Interests	340	0	0	0	0	0	0	340
Noncontrolling Interest, Decrease from Deconsolidation	-63	0	0	0	0	0	0	-63
Other	-4	0	-3	-2	0	0	-5	1
Stockholders' Equity, Period Increase (Decrease)	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

Consolidated_Statement_of_Cash

Consolidated Statement of Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
OPERATING ACTIVITIES:
Net income (loss)	$2,339		$668		$1,065
Adjustments to reconcile to net cash provided (used) by operating activities:
Depreciation and amortization	1,176		815		756
Provision (benefit) for deferred income taxes	1,264		424		206
Net (gain) loss on dispositions of assets	56		28		-52
Gain on reconsolidation of Wilpro entities (Note 4)	0		0		-144
Amortization of stock-based awards	53		37		36
Gain on remeasurement of equity-method investment	-2,544	[1]	0	[1]	0	[1]
Cash provided (used) by changes in current assets and liabilities:
Accounts and notes receivable	-276		35		27
Inventories	-36		-17		5
Other current assets and deferred charges	-44		25		29
Accounts payable	-8		-35		-110
Accrued liabilities	-203		175		0
Other, including changes in noncurrent assets and liabilities	338		62		17
Net cash provided (used) by operating activities	2,115		2,217		1,835
FINANCING ACTIVITIES:
Proceeds from (payments of) commercial paper - net	572		224		0
Proceeds from long-term debt	7,321		2,699		3,486
Payments of long-term debt	-1,828		-2,081		-1,468
Proceeds from issuance of common stock	3,416		18		2,550
Proceeds from sale of limited partner units of consolidated partnership	55		1,819		1,559
Dividends paid	-1,412		-982		-742
Dividends and distributions paid to noncontrolling interests	-840		-489		-349
Distributions paid to noncontrolling interests on sale of Wilpro assets (Note 4)	0		0		-38
Contributions from noncontrolling interests	340		467		13
Payments for debt issuance costs	-40		-15		-17
Other - net	17		17		42
Net cash provided (used) by financing activities	7,601		1,677		5,036
INVESTING ACTIVITIES:
Capital expenditures	-4,031		-3,572		-2,529
Purchases of and contributions to equity method investments	-482		-455		-2,651
Purchases of businesses, net of cash acquired	-5,958		-6		-2,049
Proceeds from dispositions of investments	0		0		79
Cash of Wilpro entities upon reconsolidation (Note 4)	0		0		121
Other - net	314		-19		108
Net cash provided (used) by investing activities	-10,157		-4,052		-6,921
Increase (decrease) in cash and cash equivalents	-441		-158		-50
Cash and cash equivalents at beginning of year	681		839		889
Cash and cash equivalents at end of year	240		681		839
Increases to property, plant, and equipment	-3,916		-3,653		-2,755
Changes in related accounts payable and accrued liabilities	-115		81		226
Capital expenditures	($4,031)		($3,572)		($2,529)
[1]	Items also included in Segment profit (loss). (See Note 19 b Segment Disclosures.)

Description_of_Business_Basis_

Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business, Basis of Presentation and Summary Of Significant Accounting Policies [Text Block]	Note 1 – Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies
	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, Access Midstream, and Williams NGL & Petchem Services reportable segments. All remaining business activities are included in Other.
	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) (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 Merger. In conjunction with the 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 merger, the Class D limited partner units of Pre-merger WPZ, all of which were held by us, were converted into WPZ common units on a one-for-one basis pursuant to the terms of the WPZ partnership agreement.  Following the Merger, we own an approximate 60 percent of the merged partnership, including the general partner interest and incentive distribution rights. In this report, we refer to the post merger partnership as “WPZ” and the pre-merger entities as “Pre-merger WPZ” and “ACMP.”
	As of December 31, 2014, our Williams Partners segment consists of our consolidated master limited partnership, Pre-merger WPZ, and includes gas pipeline and domestic midstream businesses. The 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), 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). WPZ’s midstream operations are composed of significant, large-scale operations in the Rocky Mountain and Gulf Coast regions, operations in the Marcellus Shale region, and various equity-method investments in domestic natural gas gathering and processing assets and natural gas liquid (NGL) fractionation and transportation assets. WPZ’s midstream assets also include an NGL fractionator and storage facilities near Conway, Kansas, as well as an NGL light-feed olefins cracker in Geismar, Louisiana, along with associated ethane and propane pipelines, a refinery grade splitter in Louisiana, an oil sands offgas processing plant located near Fort McMurray, Alberta, and an NGL/olefin fractionation facility and butylene/butane splitter facility at Redwater, Alberta.
	As of December 31, 2014, our Access Midstream segment consists of our consolidated master limited partnership, ACMP, which provides domestic gathering, treating, and compression services to producers under long-term, fixed-fee contracts in the Marcellus and Utica shale plays, as well as the Eagle Ford, Haynesville, Barnett, Mid-Continent, and Niobrara areas. ACMP also includes a 49 percent equity-method investment in Utica East Ohio Midstream, LLC (UEOM), a 50 percent equity-method investment interest in the Delaware Basin gas gathering system in the Mid-Continent region, and Appalachia Midstream Services, LLC, a wholly owned subsidiary, which owns an approximate average 45 percent interest in 11 gas gathering systems in the Marcellus Shale (Appalachia Midstream Investments). We previously owned an equity-method investment in ACMP until July 1, 2014, at which time we acquired all of the interests in ACMP previously held by Global Infrastructure Partners II (GIP), which included 50 percent of the general partner interest and 55.1 million limited partner units for $5.995 billion in cash (ACMP Acquisition). (See Note 2 – Acquisitions.)
	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 extractions plant).
	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), 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. These operations were previously reported within the Williams NGL & Petchem Services segment, but are now reported within Williams Partners. Prior period segment disclosures have been recast for this transaction.
	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 incentive distribution rights (IDRs) with respect to the November 2014 distribution.
	Consolidated master limited partnerships
	During the third quarter of 2014, Pre-merger WPZ issued 1,080,448 common units pursuant to an equity distribution agreement between Pre-merger WPZ and certain banks. Considering this, as well as our contribution of certain Canadian assets discussed above, and Pre-merger WPZ’s quarterly distribution of additional paid-in-kind Class D units to us, we own approximately 66 percent of the interests in Pre-merger WPZ, including the interests of the general partner, which are wholly owned by us, and IDRs as of December 31, 2014.
	Following the ACMP Acquisition on July 1, 2014, we owned approximately 50 percent of the limited partner units, including all of the Class B units that pay quarterly distribution of additional paid-in-kind Class B units. During the second half of 2014, we received quarterly distributions of additional paid-in-kind Class B units and own 51 percent of the interests in ACMP, including the interests of the general partner, which are wholly owned by us, and IDRs as of December 31, 2014.
	The previously described equity issuances by Pre-merger WPZ and ACMP had the combined net impact of increasing Noncontrolling interests in consolidated subsidiaries by $137 million, and decreasing Capital in excess of par value by $73 million, Deferred income taxes by $44 million and Accumulated other comprehensive income (loss) by $20 million in the Consolidated Balance Sheet.
	Pre-merger WPZ and ACMP are both self-funding and maintain separate lines of bank credit and cash management accounts. Pre-merger WPZ also has a commercial paper program. (See Note 14 – Debt, Banking Arrangements, and Leases.) Cash distributions from Pre-merger WPZ and ACMP to us, including any associated with our IDRs, occur through the normal partnership distributions from Pre-merger WPZ and ACMP to their respective partners.
	Discontinued operations
	The discontinued operations presented in the accompanying consolidated financial statements and notes primarily reflect gains in 2012 associated with certain of our former Venezuela operations. (See Note 4 – Discontinued Operations.)
	Unless indicated otherwise, the information in the Notes to Consolidated Financial Statements relates to our continuing operations.
	Related party transaction
	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 $115 million and $131 million in Service revenues in the Consolidated Statement of Income from this company for transportation and storage of natural gas for the years ended December 31, 2014 and 2013, respectively. This board member does not have any material interest in any transactions between the energy services company and us and he had no role in any such transactions.
	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 in entities 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 Income 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 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. 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 postretirement benefits. Our current and noncurrent regulatory asset and liability balances for the years ended December 31, 2014 and 2013 are as follows:
		December 31,
		2014		2013
		(Millions)
	Current assets reported within Other current assets and deferred charges	$	81	$	39
	Noncurrent assets reported within Regulatory assets, deferred charges, and other	337		353
	Total regulated assets	$	418	$	392
	Current liabilities reported within Accrued liabilities	$	11	$	19
	Noncurrent liabilities reported within Other noncurrent liabilities	375		329
	Total regulated liabilities	$	386	$	348
	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. (See Note 11 – Property, Plant, and Equipment.)
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 Income.
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. 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 Income, except for regulated entities, for which the liability is offset by a regulatory asset as management expects to recover amounts in future rates. 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.
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 Income.
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 Income. 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 Income 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 Income.
Certain gains and losses on derivative instruments included in the Consolidated Statement of Income 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.
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
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. The latter is included in Other income (expense) – net below Operating income (loss) in the Consolidated Statement of Income. 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
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
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 accumulated other comprehensive income 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.
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
Basic earnings (loss) per common share in the Consolidated Statement of Income 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 Income includes any dilutive effect of stock options, nonvested restricted stock units, and convertible debt, unless otherwise noted. Beginning in 2012, we have unvested service-based restricted stock units that contain a nonforfeitable right to dividends during the vesting period and are considered participating securities. Basic and diluted earnings (loss) per common share are calculated using the two-class method and the treasury-stock method. Whichever method results in the most dilutive earnings (loss) per common share is reported.
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 income 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.
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 the Consolidated Statement of Income.
Accounting standards issued but not yet adopted
In May 2014, the Financial Accounting Standards Board issued Accounting Standards Update 2014-09 establishing Accounting Standards Codification Topic 606, “Revenue from Contracts with Customers” (ASC 606). ASC 606 establishes a comprehensive new revenue recognition model designed to depict the transfer of goods or services to a customer in an amount that reflects the consideration the entity expects to be entitled to receive in exchange for those goods or services and requires significantly enhanced revenue disclosures. The standard is effective for annual reporting periods beginning after December 15, 2016, and interim periods within the reporting period. Accordingly, we will adopt this standard in the first quarter of 2017. ASC 606 allows either full retrospective or modified retrospective transition and early adoption is not permitted. We continue to evaluate both the impact of this new standard on our consolidated financial statements and the transition method we will utilize for adoption.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2014
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 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. As of December 31, 2014, we owned approximately 50 percent of the limited partnership units and 100 percent of the 2 percent general partner interest which includes IDRs. As a result of acquiring these additional interests, we obtained control of and now consolidate ACMP.
	ACMP owns, operates, develops, and acquires natural gas gathering systems and other midstream energy assets. The purpose of the acquisition is 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.
	We accounted for the ACMP Acquisition using the business combination method of accounting, which requires, among other things, that identifiable assets acquired and liabilities assumed be recognized 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, we recognized a $2.5 billion non-cash gain within the Gain on remeasurement of equity-method investment line item in the Consolidated Statement of Income.
	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 preliminary allocation of the acquisition-date fair value of the major classes of the assets acquired, which are presented in the Access Midstream segment, liabilities assumed, and noncontrolling interest at July 1, 2014. The allocation is considered preliminary because the valuation work has not been completed due to the ongoing review of the valuation results and validation of significant inputs and assumptions. Significant changes since the allocation disclosed in the third quarter reflect an increase in investments and decreases in goodwill, other intangible assets, and property, plant and equipment - net, generally associated with the attribution of fair value between consolidated and non-consolidated operations. The fair value of accounts receivable acquired equals contractual amounts receivable.
		(Millions)
	Accounts receivable	$	168
	Other current assets	63
	Investments	5,872
	Property, plant, and equipment - net	7,015
	Goodwill	474
	Other intangible assets	9,009
	Current liabilities	(408		)
	Debt	(4,052		)
	Other noncurrent liabilities	(9		)
	Noncontrolling interest in ACMP’s subsidiaries	(958		)
	Noncontrolling interest in ACMP	(6,544		)
	The goodwill recognized in the acquisition relates primarily to enhancing and diversifying our basin positions and was allocated to the reporting units representing the northeast, central, and west regions within our Access Midstream segment. Substantially all of the goodwill is expected to be deductible for tax purposes.
	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 is 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. Approximately 56 percent of the expected future revenues from these contractual customer relationships are 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, the weighted-average periods to the next renewal or extension of the existing customer contracts is approximately 17 years.
	The non-cash 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 are $16 million and are reported within our Access Midstream segment and included in Selling, general, and administrative expenses in our Consolidated Statement of Income. Direct transaction costs associated with financing commitments are $9 million and reported within Interest incurred in our Consolidated Statement of Income. Equity earnings (losses) includes $19 million of equity losses associated with certain compensation-related costs at Access Midstream that were triggered by the acquisition.
	Laser and Caiman
	On February 17, 2012, WPZ completed the acquisition of 100 percent of the ownership interests in certain entities from Delphi Midstream Partners, LLC, in exchange for $325 million in cash, net of cash acquired in the transaction, and 7,531,381 WPZ common units valued at $441 million (Laser Acquisition). The fair value of the common units issued as part of the consideration paid was determined on the basis of the closing market price of WPZ’s common units on the acquisition date, adjusted to reflect certain time-based restrictions on resale. The acquired entities primarily own the Laser Gathering System, which is comprised of a natural gas pipeline and associated gathering facilities in the Marcellus Shale in Susquehanna County, Pennsylvania, as well as gathering lines in southern New York.
	On April 27, 2012, WPZ completed the acquisition of 100 percent of the ownership interests in Caiman Eastern Midstream, LLC, from Caiman Energy, LLC in exchange for $1.72 billion in cash and 11,779,296 WPZ common units valued at $603 million (Caiman Acquisition). The fair value of the common units issued as part of the consideration paid was determined on the basis of the closing market price of WPZ’s common units on the acquisition date, adjusted to reflect certain time-based restrictions on resale. The acquired entity operates a gathering and processing business in northern West Virginia, southwestern Pennsylvania, and eastern Ohio. Acquisition transaction costs of $16 million were incurred during 2012 related to the Caiman Acquisition and are reported in Selling, general, and administrative expenses at Williams Partners in the Consolidated Statement of Income.
	The following table presents the allocation of the acquisition-date fair value of the major classes of the net assets, which are included in the Williams Partners segment:
		Laser			Caiman
		(Millions)
	Assets held-for-sale	$	18		$	—
	Other current assets	3			16
	Property, plant, and equipment	158			656
	Intangible assets	318			1,393
	Current liabilities	(21		)	(94		)
	Noncurrent liabilities	—			(3		)
	Identifiable net assets acquired	476			1,968
	Goodwill	290			356
		$	766		$	2,324
	Revenues and earnings related to the Laser and Caiman Acquisitions included within the Consolidated Statement of Income in 2012 are not material.

Variable_Interest_Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2014
Variable Interest Entity Disclosures [Abstract]
Variable Interest Entities [Text Block]	Note 3 – Variable Interest Entities
	Consolidated VIEs
	As of December 31, 2014, 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. WPZ is the primary beneficiary because it has the power to direct the activities that most significantly impact Gulfstar One’s economic performance. WPZ, as construction agent for Gulfstar One, designed, constructed, and installed a proprietary floating-production system, Gulfstar FPS™, and associated pipelines which began providing production handling and gathering services for the Tubular Bells oil and gas discovery in the eastern deepwater Gulf of Mexico in the fourth quarter of 2014. WPZ received certain advance payments from the producer customers. In certain circumstances, the producer customers could be responsible for Gulfstar One’s unrecovered portion of the firm price of building the facilities if the production handling agreement is terminated. 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 quarter of 2016. The current estimate of the total remaining construction costs for the expansion project is approximately $150 million, which we expect will 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 agent for Constitution, is building a pipeline connecting our 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 second half of 2016 and estimates the total remaining construction costs of the project to be approximately $628 million, which will be funded with capital contributions from WPZ and the other equity partners on a proportional basis.
	Cardinal
	ACMP owns a 66 percent interest in Cardinal Gas Services, L.L.C (Cardinal Venture), a subsidiary that, due to certain risks shared with customers, is a VIE. ACMP is the primary beneficiary because it has the power to direct the activities that most significantly impact Cardinal Venture’s economic performance. ACMP, as operator for Cardinal Venture, designed, constructed, and installed associated pipelines which will initially provide production handling and gathering services for the Utica region. ACMP has received certain advance payments from the equity partners during the construction process.
	Jackalope
	ACMP owns a 50 percent interest in Jackalope Gas Gathering Services, L.L.C (Jackalope Venture), a subsidiary that, due to certain risks shared with customers, is a VIE. ACMP is the primary beneficiary because it has the power to direct the activities that most significantly impact Jackalope Venture’s economic performance. ACMP, as operator for Jackalope Venture, designed, constructed, and installed associated pipelines which will initially provide production handling and gathering services for the Niobrara region. ACMP has received certain advance payments from the equity partners during the construction process.
	The following table presents amounts included in our Consolidated Balance Sheet that are for the use or obligation of our consolidated VIEs.
		December 31,
		2014			2013 (1)			Classification
		(Millions)
	Assets (liabilities):
	Cash and cash equivalents	$	113		$	130		Cash and cash equivalents
	Accounts receivable	52			—			Accounts and notes receivable – net - Trade and other
	Other current assets	3			—			Other current assets and deferred charges
	Property, plant, and equipment – net	2,794			1,113			Property, plant, and equipment – net
	Goodwill	103			—			Goodwill
	Other intangible assets, net	1,493			—			Other intangible assets- net of accumulated amortization
	Other noncurrent assets	14			—			Regulatory assets, deferred charges, and other
	Accounts payable	(48		)	(146		)	Accounts payable
	Accrued liabilities	(36		)	(3		)	Accrued liabilities
	Current deferred revenue	(45		)	(10		)	Accrued liabilities
	Noncurrent deferred income taxes	(13		)	—			Deferred income taxes
	Asset retirement obligation	(94		)	—			Other noncurrent liabilities
	Noncurrent deferred revenue associated with customer advance payments	(395		)	(115		)	Other noncurrent liabilities
	-1	Amounts presented for December 31, 2013, include balances related to Bluegrass Pipeline. See discussion of the subsequent deconsolidation of Bluegrass Pipeline below.
	Nonconsolidated VIEs
	Laurel Mountain
	In October 2014, Laurel Mountain Midstream, LLC (Laurel Mountain) a previously reported VIE, was restructured removing the customer risk sharing provisions and is no longer considered a VIE as of December 31, 2014. Laurel Mountain continues to be reported as a 69 percent-owned equity-method investment due to the significant participatory rights of our partners such that we do not have control of Laurel Mountain.
	Caiman II
	During April 2014, Caiman Energy II, LLC (Caiman II), a previously reported VIE, became able to finance its current activities without additional subordinated financial support due in part to its primary investee, Blue Racer Midstream LLC, securing a revolving credit agreement with a third party. As a result, Caiman II is no longer a VIE but continues to be reported as a 58 percent-owned equity-method investment due to the significant participatory rights of our partners such that we do not have control of Caiman II.
	Bluegrass Pipeline
	We owned a 50 percent equity-method investment in Bluegrass Pipeline, which was a proposed NGL pipeline that would connect processing facilities in the Marcellus and Utica shale-gas areas in the northeastern United States to growing petrochemical and export markets in the Gulf Coast area of the United States. Bluegrass Pipeline was considered to be a VIE because it had insufficient equity to finance activities during its development stage. From its inception until February 16, 2014, we were the primary beneficiary of this entity because we had the power to direct whether the project moved forward and thus we previously consolidated the Bluegrass Pipeline.
	On February 16, 2014, we and our partner executed an amendment to the governing documents that removed our power to direct whether the project moved forward. As a result, we were no longer the primary beneficiary as of that date, and we deconsolidated the Bluegrass Pipeline and began reporting our 50 percent interest as an equity-method investment. There was no gain or loss recognized upon deconsolidation.
	Based on a lack of customer commitments and other factors, our management decided in April 2014 to discontinue further funding of the project. The capitalized project development costs at the Bluegrass Pipeline entity were written off as of March 31, 2014, and as a result, we recognized $67 million in related equity losses in the first quarter of 2014. On September 2, 2014, we received a notice of dissolution from our partner with respect to the Bluegrass Pipeline entity and the related Moss Lake entities. We completed the dissolution process for Bluegrass Pipeline in the fourth quarter of 2014.
	Moss Lake
	We owned 50 percent equity-method investments in Moss Lake Fractionation LLC and Moss Lake LPG Terminal LLC (collectively referred to as Moss Lake) which were considered to be VIEs because they had insufficient equity to finance activities during their development stage. Moss Lake was being developed to construct a proposed large-scale fractionation plant, expand natural gas liquids storage facilities in Louisiana and construct a proposed pipeline connecting these facilities to the Bluegrass Pipeline. Additionally, Moss Lake would construct a proposed new liquefied petroleum gas (LPG) terminal. We were not the primary beneficiary of this entity because we did not have the power to direct the majority of the activities of Moss Lake that most significantly impact its economic performance at this stage. In the first quarter of 2014, we recognized $4 million in equity losses related to Moss Lake, primarily associated with the underlying write-off of capitalized project development costs at Moss Lake. As a result of the circumstances noted above in our Bluegrass Pipeline discussion, on September 2, 2014, we received a notice of dissolution from our partner with respect to the Bluegrass Pipeline entity and Moss Lake entities. We completed the dissolution process for Moss Lake in the fourth quarter of 2014.

Discontinued_Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Discontinued Operations [Text Block]	Note 4 – Discontinued Operations
	Income (loss) from discontinued operations for 2013 reflects a $15 million pretax charge resulting from an unfavorable ruling associated with our former Alaska refinery related to the Trans-Alaska Pipeline System Quality Bank.
	Income (loss) from discontinued operations for 2012 reflects a $144 million pretax gain on reconsolidation related to our majority ownership in entities (the Wilpro entities) that owned and operated the El Furrial and PIGAP II gas compression facilities prior to their expropriation by the Venezuelan government in May 2009. We deconsolidated the Wilpro entities in 2009. In 2012, the El Furrial and PIGAP II assets were sold as part of a settlement related to the 2009 expropriation of these assets. Upon closing, the lenders that had provided financing for these operations were repaid in full, and the Wilpro entities received $98 million in cash and the right to receive quarterly cash installments of $15 million (receivable) plus interest through the first quarter of 2016.  Following the settlement and repayment in full of the lenders, we reestablished control and, therefore, reconsolidated the Wilpro entities and recognized the gain on reconsolidation. This gain reflected our share of the cash, including cash received in the settlement, and the estimated fair value of the receivable held by the Wilpro entities at the time of reconsolidation.
	To determine the fair value of the receivable at the time of reconsolidation, we considered both quantitative (income) and qualitative (market) approaches. Under our quantitative 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 under similar circumstances, our likelihood of using arbitration if the counterparty does not perform, and discount rates. Our qualitative analysis utilized information as to how similar notes might be valued. This analysis also reduced the value due to its limited marketability as the payment terms are embedded within the overall settlement agreement. Both analyses resulted in similar fair values. Ultimately we determined the fair value of the receivable to be $88 million at the time of reconsolidation, utilizing a probability-weighted cash flow analysis with a discount rate of approximately 12 percent and a probability of default ranging from 15 percent to 100 percent. Utilizing different assumptions regarding the collectability of the receivable and discount rates could have resulted in a materially different fair value.

Investing_Activities

Investing Activities	12 Months Ended
	Dec. 31, 2014
Investments [Abstract]
Investing Activities [Text Block]	Note 5 – Investing Activities
	Investing Income
		Years Ended December 31,
		2014			2013			2012
		(Millions)
	Gain on remeasurement of equity-method investment (1)	$	2,544		$	—		$	—
	Equity earnings (losses) (1)	144			134			111
	Income (loss) from investments (1)	—			28			49
	Interest income and other	43			53			28
	Total investing income	$	2,731		$	215		$	188
	__________
	-1	Items also included in Segment profit (loss). (See Note 19 – Segment Disclosures.)
	Gain on remeasurement of equity-method investment
	We recognized a non-cash gain in 2014 associated with the ACMP Acquisition. (See Note 2 – Acquisitions.)
	Equity earnings (losses)
	Equity earnings (losses) in 2014 includes:
	•	$146 million of equity earnings for the last six months of the year from equity-method investments acquired in the ACMP acquisition, partially offset by $49 million of noncash amortization of the difference between the cost of our investment and our underlying share of the net assets (See Note 2 – Acquisitions.);
	•	Write-offs of capitalized project development costs on our discontinued investments in Bluegrass Pipeline of $67 million and Moss Lake of $4 million (See Note 3 – Variable Interest Entities.);
	•	$23 million of equity earnings recognized from our interest in ACMP that was accounted for under the equity-method of accounting for the first six months of the year, more than offset by $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, offset by $63 million noncash amortization of the difference between the cost of our investment and our underlying share of the net assets.
	Income (loss) from investments
	Included in Income (loss) from investments for 2013 is 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.
	In 2010, we sold our 50 percent interest in Accroven SRL (Accroven) to the state-owned oil company, Petróleos de Venezuela S.A. Income (loss) from investments in 2012 includes a gain of $53 million from the sale. Payments were recognized upon receipt, as future collections were not reasonably assured.
	Interest income and other
	Interest income and other includes $41 million, $50 million, and $7 million of interest income for 2014, 2013 and 2012, respectively, associated with a receivable related to the sale of certain former Venezuela assets. (See Note 4 – Discontinued Operations.) The 2014 and 2013 amounts reflect an increase in yield associated with a revision in our estimate of the cash flows expected to be received as a result of continued timely payment by the counterparty. Additionally, Interest income and other for 2012 includes $10 million of interest related to the 2010 sale of Accroven discussed above.
	Investments
		December 31,
		2014			2013
		(Millions)
	Equity method:
	Appalachia Midstream Investments (2)	$	3,033		$	—
	Delaware Basin gas gathering system — 50% (2)	1,478			—
	UEOM — 49% (2)	1,411			—
	Discovery Producer Services LLC (Discovery) — 60% (1)	602			527
	Laurel Mountain — 69% (1)	459			481
	Overland Pass Pipeline Company LLC (OPPL) — 50%	453			452
	Caiman II — 58% (1)	432			256
	Gulfstream — 50%	317			333
	Access Midstream Partners — 24% in 2013	—			2,161
	Other	215			150
		$	8,400		$	4,360
	___________
	-1	We account for these investments under the equity method of accounting due to the significant participatory rights of our partners such that we do not control or are otherwise not the primary beneficiary of the investments.
	-2	We acquired these investments in the ACMP Acquisition. (Note 2 – Acquisitions.) As discussed in Note 1 – Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies, the Appalachia Midstream Investments include investments in 11 different gathering systems in the Marcellus Shale. Ownership interests range from 33.75 percent to 67.50 percent, resulting in an overall approximate average interest of 45 percent. For those investments where we own in excess of 50 percent, we apply the equity-method of accounting due to the significant participation rights of our partners such that we do not control.
	Related party transactions
	We have purchases from our equity-method investees included in Product costs in the Consolidated Statement of Income of $197 million, $161 million, and $186 million for the years ended 2014, 2013, and 2012, respectively. We have $13 million and $13 million included in Accounts payable in the Consolidated Balance Sheet with our equity-method investees at December 31, 2014 and 2013, 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 Income are $75 million, $67 million and $75 million for the years ended 2014, 2013, and 2012, respectively.
	Equity-method investments
	We have differences between the carrying value of our equity-method investments and the underlying equity in the net assets of the investees of $3.7 billion at December 31, 2014. This difference primarily relates 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. (See Note 2 – Acquisitions.)
	We generally fund our portion of significant expansion or development projects of these investees through additional capital contributions. As of December 31, 2014, our proportionate share of amounts remaining to be spent for specific capital projects already in progress for Discovery and Laurel Mountain totaled $98 million and $92 million, respectively. See the table below for significant contributions.
		2014			2013			2012
		(Millions)
	Caiman II	$	175		$	192		$	69
	Discovery	106			193			169
	Appalachia Midstream Investments	84			—			—
	UEOM	57			—			—
	Delaware Basin gas gathering system	20			—			—
	Laurel Mountain	12			42			174
	The organizational documents of entities in which we have an equity-method interest generally require distribution of available cash to members on a quarterly basis. Dividends and distributions, including those presented below, received from companies accounted for by the equity method of accounting were $409 million, $247 million, and $173 million in 2014, 2013, and 2012, respectively. These transactions reduced the carrying value of our investments. These dividends and distributions primarily included:
		2014			2013			2012
		(Millions)
	Appalachia Midstream Investments	$	120		$	—		$	—
	Gulfstream	81			81			79
	Access Midstream	64			93			—
Laurel Mountain	39			—			—
Discovery	36			12			21
OPPL	27			27			28
Aux Sable Liquid Products L.P.	15			20			28
Summarized Financial Position and Results of Operations of All Equity-Method Investments
	December 31,
	2014			2013
	(Millions)
Assets (liabilities):
Current assets	$	599		$	689
Noncurrent assets	9,135			13,621
Current liabilities	(850		)	(573		)
Noncurrent liabilities	(954		)	(4,563		)
Noncontrolling interest	—			(254		)
	Years Ended December 31,
	2014			2013			2012
	(Millions)
Gross revenue	$	1,623		$	2,406		$	1,821
Operating income	534			699			557
Net income	460			627			488

Other_Income_and_Expense

Other Income and Expense	12 Months Ended
	Dec. 31, 2014
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 Income:
		Years Ended December 31,
		2014			2013			2012
		(Millions)
	Williams Partners
	Contingency gain settlement	$	(154	)	$	—		$	—
	Impairment of certain materials and equipment (See Note 17)	40			—			—
	Net gain related to partial acreage dedication release	(12		)	—			—
	Amortization of regulatory assets associated with asset retirement obligations	33			30			7
	Write-off of the Eminence abandonment regulatory asset not recoverable through rates	(3		)	12			—
	Insurance recoveries associated with the Eminence abandonment	—			(16		)	—
	Project feasibility costs	2			4			21
	Capitalization of project feasibility costs previously expensed	(5		)	(1		)	(19		)
	Loss associated with a producer claim	—			25			—
	Access Midstream
	Loss related to sale of certain assets	10			—			—
	Impairment of certain materials and equipment held for sale (See Note 17)	12			—			—
	Williams NGL & Petchem Services
	Write-off of an abandoned project	—			20			—
	The reversals of project feasibility costs from expense to capital at Williams Partners are associated with natural gas pipeline expansion projects. These reversals were made upon determining that the related projects were probable of development. These costs are now included in the capital costs of the projects, which we believe are probable of recovery through the project rates.
	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 has been 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 (Geismar Incident) rendered the facility temporarily inoperable and resulted in significant human, financial, and operational effects.
	At the time of the incident, we had insurance coverage for repair and replacement costs, lost production, and additional expenses related to the incident as follows:
	•	Property damage and business interruption coverage with a combined per-occurrence limit of $500 million and retentions (deductibles) of $10 million per occurrence for property damage and a waiting period of 60 days per occurrence for business interruption;
	•	General liability coverage with per-occurrence and aggregate annual limits of $610 million and retentions (deductibles) of $2 million per occurrence;
	•	Workers’ compensation coverage with statutory limits and retentions (deductibles) of $1 million total per occurrence.
	We expensed $13 million at Williams Partners during 2013 of costs under our insurance deductibles reported in Operating and maintenance expenses in the Consolidated Statement of Income. During the years ended December 31, 2014 and 2013, we received $246 million and $50 million, respectively, of insurance recoveries related to the Geismar Incident. These amounts are reported within Williams Partners and reflected as gains in Net insurance recoveries – Geismar Incident in our Consolidated Statement of Income. Also, during the years ended December 31, 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.
	Additional Items
	The year ended December 31, 2014, includes $18 million of project development costs related to the Bluegrass Pipeline reported within Williams NGL & Petchem Services and reflected in Selling, general, and administrative expenses in the Consolidated Statement of Income.
	Selling, general, and administrative expenses in 2014 includes $15 million of employee-related transition costs and $11 million of consulting, legal, and accounting fees related to the Merger reported primarily within the Access Midstream segment, in addition to $10 million of general corporate expenses associated with integration and re-alignment of resources. Operating and maintenance expenses in 2014 also includes $15 million of employee-related transition costs associated with the Merger reported within the Access Midstream segment.
	Other income (expense) – net below Operating income (loss) includes $44 million, $22 million, and $21 million for allowance for equity used during construction (AFUDC) for the years ended December 31, 2014, 2013, and 2012, respectively. AFUDC increased during 2014 due to the increase in spending on Constitution and various Transco expansion projects.
	We engaged a consulting firm in 2012 to assist in better aligning resources to support our business strategy following the spin-off of WPX Energy, Inc. (WPX). In 2012, we recorded $26 million of reorganization-related costs, including consulting costs, to Selling, general, and administrative expenses.

Provision_Benefit_for_Income_T

Provision (Benefit) for Income Taxes	12 Months Ended
	Dec. 31, 2014
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,
		2014			2013			2012
		(Millions)
	Current:
	Federal	$	(9	)	$	(17	)	$	91
	State	2			7			17
	Foreign	10			(13		)	40
		3			(23		)	148
	Deferred:
	Federal	1,108			348			220
	State	119			40			(13		)
	Foreign	19			36			5
		1,246			424			212
	Total provision (benefit)	$	1,249		$	401		$	360
	Reconciliations from the Provision (benefit) for income taxes at the federal statutory rate to the recorded Provision (benefit) for income taxes are as follows:
		Years Ended December 31,
		2014			2013			2012
		(Millions)
	Provision (benefit) at statutory rate	$	1,255		$	378		$	451
	Increases (decreases) in taxes resulting from:
	Impact of nontaxable noncontrolling interests	(75		)	(78		)	(72		)
	State income taxes (net of federal benefit)	82			26			2
	Foreign operations – net	(11		)	(32		)	(36		)
	Taxes on undistributed earnings of foreign subsidiaries – net	(37		)	99			—
	Other – net	35			8			15
	Provision (benefit) for income taxes	$	1,249		$	401		$	360
	Income (loss) from continuing operations before income taxes includes $102 million, $119 million, and $196 million of foreign income in 2014, 2013, and 2012, respectively.
	The December 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.
	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 consider 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 tax benefit in AOCI during the fourth quarter of 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. As a result of the retroactive extension of bonus depreciation late in the fourth quarter of 2014, the amount previously estimated to be included in current tax liability will remain in deferred tax liability.
	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 tax provision to the federal statutory rate.
	Significant components of deferred tax liabilities and deferred tax assets are as follows:
		December 31,
		2014			2013
		(Millions)
	Deferred tax liabilities:
	Property, plant, and equipment	$	4		$	102
	Undistributed earnings of foreign subsidiaries	—			75
	Investments	5,472			3,663
	Other	10			—
	Total deferred tax liabilities	5,486			3,840
	Deferred tax assets:
	Accrued liabilities	178			126
	Minimum tax credits	137			66
	Foreign tax credit	251			42
	Federal loss carryovers	134			—
	State losses and credits	250			194
	Other	97			91
	Total deferred tax assets	1,047			519
	Less valuation allowance	206			181
	Net deferred tax assets	841			338
	Overall net deferred tax liabilities	$	4,645		$	3,502
	The valuation allowance at December 31, 2014 and 2013 serves to reduce the available deferred tax assets to an amount that will, more likely than not, be realized based primarily upon management’s estimate of future reversals of existing taxable temporary differences. 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 2015 and 2034 with some carryovers having indefinite carryforward periods. In the case of the valuation allowance, the change is due to the ongoing evaluation process of the losses and credits anticipated to be realized in future years. The federal tax minimum tax credits of $137 million currently have no expiration dates. $139 million of foreign tax credit 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 tax liabilities associated with temporary differences on foreign assets and liabilities become current tax liabilities in the foreign jurisdiction.
	Federal net operating loss carryovers and charitable contribution carryovers of $449 million at the end of 2014 are expected to be utilized prior to expiration between 2018 and 2034. 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 tax benefit for these items, the additional tax benefit is not recognized until the deduction reduces current taxes payable. Since the additional tax benefit does not reduce our current taxes payable for 2014, these tax benefits are not included in our Federal loss carryovers deferred tax asset. The additional tax benefit deductible for tax purposes but not included in our Federal loss carryovers deferred tax asset as of December 31, 2014 totaled $23 million.
	Cash payments for income taxes (net of refunds and discontinued operations) in 2014 and 2012 were $29 million and $198 million, respectively. During 2013, we received cash refunds (net of payments) for income taxes of $50 million.
	As of December 31, 2014, we had approximately $89 million of unrecognized tax benefits. If recognized, income tax expense would be reduced by $86 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:
		2014			2013
		(Millions)
	Balance at beginning of period	$	66		$	58
	Additions based on tax positions related to the current year	11			4
	Additions for tax positions of prior years	12			18
	Reductions for tax positions of prior years	—			(2		)
	Settlement with taxing authorities	—			(12		)
Balance at end of period	$	89		$	66
We recognize related interest and penalties as a component of income tax provision. Total interest and penalties recognized as part of income tax provision were expenses of $8 million and $9 million for 2014 and 2013, respectively, and a benefit of $7 million for 2012. Approximately $24 million and $16 million of interest and penalties primarily relating to uncertain tax positions have been accrued as of December 31, 2014 and 2013, respectively.
As of December 31, 2014, the IRS examination of our consolidated U.S. federal income tax returns for 2011 through 2013 tax years is in process. We do not expect material changes in our financial position resulting from this examination. However, it is reasonably possible that the amount of unrecognized benefit with respect to our uncertain tax positions could decrease by up to $45 million within the next 12 months due to the effective settlement of tax issues related to past foreign operations. 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.
During the first quarter of 2013, we finalized a settlement with the IRS on tax matters related to the IRS’s examination of our 2009 and 2010 consolidated corporate income tax returns. We recorded a tax provision of approximately $2 million related to these matters during the third quarter of 2012. With respect to the examined years, we made cash payments of $12 million to the IRS in February 2013.
On September 13, 2013, the IRS issued final regulations providing guidance on the treatment of amounts paid to acquire, produce, or improve tangible property, and proposed regulations providing guidance on the dispositions of such 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. Changes for tax treatment elected by us or required by the regulations will generally be effective prospectively; however, implementation of many of the regulations’ provisions will require a calculation of the cumulative effect of the changes on prior years, and it is expected that such amount will have to be included in the determination of our taxable income in 2014, or possibly over a four-year period beginning in 2014. Since the changes will affect the timing for deducting expenditures for tax purposes, the impact of implementation will be reflected in the amount of income taxes payable or receivable, cash flows from operations and deferred taxes beginning in 2014, with no net tax provision effect. We estimate that the regulations will result in an immaterial balance sheet only impact for businesses other than our gas transmission business. 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 additional procedural guidance from the IRS for the gas transmission and distribution industry, we cannot at this time estimate the impact of implementing the regulations.

Earnings_Loss_Per_Common_Share

Earnings (Loss) Per Common Share from Continuing Operations	12 Months Ended
	Dec. 31, 2014
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,
		2014		2013		2012
		(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	$	2,110	$	441	$	723
	Basic weighted-average shares	719,325		682,948		619,792
	Effect of dilutive securities:
	Nonvested restricted stock units	2,234		1,995		2,694
	Stock options	2,064		2,149		2,608
	Convertible debentures	18		93		392
	Diluted weighted-average shares	723,641		687,185		625,486
	Earnings (loss) per common share from continuing operations:
	Basic	$	2.93	$	0.65	$	1.17
	Diluted	$	2.91	$	0.64	$	1.15
	Beginning in 2012, we have nonvested service-based restricted stock units that contain a nonforfeitable right to dividends during the vesting period and are considered participating securities. Dividends associated with these participating securities were $4 million, $2 million and $1 million for 2014, 2013 and 2012, respectively, and have been subtracted from Income (loss) from continuing operations attributable to The Williams Companies, Inc. available to common stockholders for basic and diluted earnings (loss) per common share in the calculation of earnings (loss) per common share.

Employee_Benefit_Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	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. Effective January 1, 2014, subsidized retiree medical benefits for eligible participants age 65 and older are paid through contributions to health reimbursement accounts. Prior to January 1, 2014, subsidized retiree medical benefits for all eligible participants were provided through a self-insured retiree medical plan sponsored by us. Subsidized retiree medical benefits for eligible participants under age 65 continue to be provided by this medical plan. The impact of this plan change was reflected in the December 31, 2013, other postretirement benefit obligation. 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 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
		2014				2013				2014				2013
		(Millions)
	Change in benefit obligation:
	Benefit obligation at beginning of year	$	1,384			$	1,549			$	213			$	331
	Service cost	40				44				2				2
	Interest cost	62				51				10				11
	Plan participants’ contributions	—				—				2				6
	Benefits paid	(86		)		(87		)		(14		)		(19		)
	Medicare Part D subsidy	—				—				—				4
	Plan amendment	—				—				1				(59		)
	Actuarial loss (gain)	144				(173		)		21				(63		)
	Settlements	(3		)		—				(1		)		—
	Curtailments	—				—				(1		)		—
	Other	3				—				—				—
	Benefit obligation at end of year	1,544				1,384				233				213
	Change in plan assets:
	Fair value of plan assets at beginning of year	1,241				1,071				201				175
	Actual return on plan assets	78				165				13				31
	Employer contributions	63				92				6				8
	Plan participants’ contributions	—				—				2				6
	Benefits paid	(86		)		(87		)		(14		)		(19		)
	Settlements	(3		)		—				—				—
	Fair value of plan assets at end of year	1,293				1,241				208				201
	Funded status — underfunded	$	(251	)		$	(143	)		$	(25	)		$	(12	)
	Accumulated benefit obligation	$	1,516			$	1,359
	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,
		2014				2013
		(Millions)
	Underfunded pension plans:
	Current liabilities	$	2			$	1
	Noncurrent liabilities	249				142
	Underfunded other postretirement benefit plans:
	Current liabilities	7				8
	Noncurrent liabilities	18				4
	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 $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 pension plans’ benefit obligation Actuarial loss (gain) of $(173) million in 2013 is primarily due to the impact of an increase in the discount rates utilized to calculate the benefit obligation.
	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. The 2013 benefit obligation Actuarial loss (gain) of $(63) million for our other postretirement benefit plans is primarily due to the impact of an increase in the discount rates utilized to calculate the benefit obligation as well as favorable claims experience. The Plan amendment for the other postretirement benefit plans of $(59) million in 2013 reflects a change in the plans to provide subsidized retiree medical benefits through defined annual contributions to health reimbursement accounts for eligible participants age 65 and older effective January 1, 2014.
	At December 31, 2014 and 2013, 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
		2014				2013				2014				2013
		(Millions)
	Amounts included in Accumulated other comprehensive income (loss):
	Prior service (cost) credit	$	—			$	—			$	17			$	26
	Net actuarial loss	(593		)		(491		)		(28		)		(11		)
	Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline:
	Prior service credit	N/A				N/A				$	30			$	42
	Net actuarial loss	N/A				N/A				(4		)		(2		)
	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 $62 million at December 31, 2014 and $44 million at December 31, 2013 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
		2014				2013				2012				2014				2013			2012
	(Millions)
Components of net periodic benefit cost:
Service cost	$	40			$	44			$	39			$	2			$	2		$	3
Interest cost	62				51				55				10				11			13
Expected return on plan assets	(76		)		(61		)		(64		)		(12		)		(9		)	(9		)
Amortization of prior service cost (credit)	—				1				1				(20		)		(12		)	(7		)
Amortization of net actuarial loss	39				60				53				—				4			8
Net actuarial loss from settlements and curtailments	1				—				5				(1		)		—			—
Reclassification to regulatory liability	—				—				—				4				2			—
Net periodic benefit cost	$	66			$	95			$	89			$	(17	)		$	(2	)	$	8
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
	2014				2013				2012				2014				2013			2012
	(Millions)
Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss):
Net actuarial gain (loss)	$	(142	)		$	277			$	(51	)		$	(18	)		$	23		$	2
Prior service (cost) credit	—				—				—				(1		)		23			2
Amortization of prior service cost (credit)	—				1				1				(8		)		(4		)	(3		)
Amortization of net actuarial loss and loss from settlements and curtailments	40				60				58				1				1			3
Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss)	$	(102	)		$	338			$	8			$	(26	)		$	43		$	4
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:
		2014				2013				2012
		(Millions)
Other changes in plan assets and benefit obligations recognized in regulatory (assets) liabilities:
Net actuarial gain (loss)		$	(2	)		$	62			$	13
Prior service credit		—				36				4
Amortization of prior service credit		(12		)		(8		)		(4		)
Amortization of net actuarial loss		—				3				5
Pre-tax amounts expected to be amortized in Net periodic benefit cost in 2015 are as follows:
	Pension				Other
	Benefits				Postretirement
					Benefits
	(Millions)
Amounts included in Accumulated other comprehensive income (loss):
Prior service credit	$	—			$	(7	)
Net actuarial loss	43				1
Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline:
Prior service credit	N/A				$	(10	)
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
	2014			2013			2014			2013
Discount rate	3.96	%		4.68	%		4.12	%		4.8	%
Rate of compensation increase	4.62			4.56			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
	2014			2013			2012			2014			2013			2012
Discount rate	4.68	%		3.43	%		3.98	%		4.8	%		3.97	%		4.22	%
Expected long-term rate of return on plan assets	6.85			5.9			6.3			6.11			5.26			5.71
Rate of compensation increase	4.56			4.57			4.52			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 recently adopted generational projection mortality tables. These mortality tables generally reflect increased estimated life expectancy.
The assumed health care cost trend rate for 2015 is 6.9 percent. This rate decreases to 5.0 percent by 2023. 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	9				(7		)
Plan Assets
The investment policy for our pension and other postretirement benefit plans provides for an investment 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 pension plans’ target asset allocation range at December 31, 2014 was 54 percent to 66 percent equity securities, which includes the commingled investment funds invested in equity securities, and 36 percent to 44 percent fixed income securities, including the fixed income commingled investment fund, and cash management funds. Within equity securities, the target range for U.S. equity securities is 37 percent to 45 percent and international equity securities is 17 percent to 21 percent. The asset allocation continues to be weighted toward equity securities since the obligations of the pension and other postretirement benefit plans are long-term in nature and historically equity securities have outperformed other asset classes over long periods of time.
Equity security investments are restricted to high-quality, readily marketable securities that are actively traded on the major U.S. and foreign national exchanges. 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.
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 the direct holding of options or futures require approval and, historically, have not been used; however, these instruments may be used in commingled investment funds. Additionally, real estate equity and natural resource property investments are generally restricted.
Fixed income securities are generally restricted to high-quality, marketable securities that may include, but are not necessarily limited to, U.S. Treasury securities, U.S. government guaranteed and nonguaranteed mortgage-backed securities, government and municipal bonds, and investment grade corporate securities. The overall rating of the fixed income security assets is generally required to be at least “A,” according to the Moody’s or Standard & Poor’s rating systems. 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.
During 2014, ten active investment managers and one passive investment manager managed substantially all of the pension plans’ funds and four active investment managers and one passive investment manager managed the other postretirement benefit plans’ funds. Each of the managers had responsibility for managing a specific portion of these assets and each investment manager was responsible for 1 percent to 15 percent of the assets.
The pension and other postretirement benefit plans’ assets are held primarily in equity securities, including commingled investment funds invested in equity securities, and fixed income securities, including a commingled fund invested in fixed income securities. Within the plans’ investment securities, there are no significant concentrations of risk 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, 2014 and 2013 by asset class are as follows:
	2014
	Quoted Prices				Significant				Significant				Total
	in Active				Other				Unobservable
	Markets for				Observable				Inputs
	Identical				Inputs				(Level 3)
	Assets				(Level 2)
	(Level 1)
	(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
Commingled investment funds:
Equities — U.S. large cap (1)	—				189				—				189
Equities — International small cap (2)	—				24				—				24
Equities — Emerging markets value (3)	—				27				—				27
Equities — Emerging markets growth (4)	—				19				—				19
Equities — International developed markets large cap value (5)	—				101				—				101
Fixed income — Corporate bonds (6)	—				163				—				163
Fixed income securities (7):
U.S. Treasury securities	31				—				—				31
Mortgage-backed securities	—				65				—				65
Corporate bonds	—				222				—				222
Insurance company investment contracts and other	—				7				—				7
Total assets at fair value at December 31, 2014	$	416			$	877			$	—			$	1,293
	2013
	Quoted Prices				Significant				Significant				Total
	in Active				Other				Unobservable
	Markets for				Observable				Inputs
	Identical				Inputs				(Level 3)
	Assets				(Level 2)
	(Level 1)
	(Millions)
Pension assets:
Cash management fund	$	23			$	—			$	—			$	23
Equity securities:
U.S. large cap	211				—				—				211
U.S. small cap	146				—				—				146
International developed markets large cap growth	—				59				—				59
Preferred stock	2				—				—				2
Commingled investment funds:
Equities — U.S. large cap (1)	—				179				—				179
Equities — International small cap (2)	—				24				—				24
Equities — Emerging markets value (3)	—				34				—				34
Equities — Emerging markets growth (4)	—				19				—				19
Equities — International developed markets large cap value (5)	—				100				—				100
Fixed income — Corporate bonds (6)	—				140				—				140
Fixed income securities (7):
U.S. Treasury securities	30				—				—				30
Mortgage-backed securities	—				67				—				67
Corporate bonds	—				200				—				200
Insurance company investment contracts and other	—				7				—				7
Total assets at fair value at December 31, 2013	$	412			$	829			$	—			$	1,241
The fair values of our other postretirement benefits plan assets at December 31, 2014 and 2013 by asset class are as follows:
	2014
	Quoted Prices				Significant				Significant				Total
	in Active				Other				Unobservable
	Markets for				Observable				Inputs
	Identical				Inputs				(Level 3)
	Assets				(Level 2)
	(Level 1)
	(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
Commingled investment funds:
Equities — U.S. large cap (1)	—				19				—				19
Equities — International small cap (2)	—				2				—				2
Equities — Emerging markets value (3)	—				3				—				3
Equities — Emerging markets growth (4)	—				2				—				2
Equities — International developed markets large cap value (5)	—				10				—				10
Fixed income — Corporate bonds (6)	—				16				—				16
Fixed income securities (8):
U.S. Treasury securities	3				—				—				3
Government and municipal bonds	—				11				—				11
Mortgage-backed securities	—				7				—				7
Corporate bonds	—				23				—				23
Total assets at fair value at December 31, 2014	$	98			$	110			$	—			$	208
	2013
	Quoted Prices				Significant				Significant				Total
	in Active				Other				Unobservable
	Markets for				Observable				Inputs
	Identical				Inputs				(Level 3)
	Assets				(Level 2)
	(Level 1)
	(Millions)
Other postretirement benefit assets:
Cash management funds	$	13			$	—			$	—			$	13
Equity securities:
U.S. large cap	52				—				—				52
U.S. small cap	29				—				—				29
International developed markets large cap growth	—				15				—				15
Emerging markets growth	1				1				—				2
Commingled investment funds:
Equities — U.S. large cap (1)	—				18				—				18
Equities — International small cap (2)	—				2				—				2
Equities — Emerging markets value (3)	—				4				—				4
Equities — Emerging markets growth (4)	—				2				—				2
Equities — International developed markets large cap value (5)	—				10				—				10
Fixed income — Corporate bonds (6)	—				14				—				14
Fixed income securities (8):
U.S. Treasury securities	3				—				—				3
Government and municipal bonds	—				10				—				10
Mortgage-backed securities	—				7				—				7
Corporate bonds	—				20				—				20
Total assets at fair value at December 31, 2013	$	98			$	103			$	—			$	201
____________
-1	The stated intent of this fund is to invest primarily in equity securities comprising the Standard & Poor’s 500 Index. The investment objective of the fund is to approximate the performance of the Standard & Poor’s 500 Index over the long term. The fund manager retains the right to restrict withdrawals from the fund so as not to disadvantage other investors in the fund.
-2	The stated intent of this fund is to invest in equity securities of international small capitalization companies for the purpose of capital appreciation. The fund invests primarily in equity securities of non-U.S. issuers and other Depository Receipts listed on globally recognized exchanges. The fund may also invest up to 15 percent of its net asset value in emerging markets. The plans’ trustee is required to notify the fund manager 10 days prior to a withdrawal from the fund. For any redemption made within 180 days of contribution, the fund reserves the right to charge a 1.5 percent redemption fee. The fund also reserves the right to make all or a portion of redemptions in-kind rather than in cash or in a combination of cash and in-kind.
-3	The stated intent of this fund is to invest in equity securities of international emerging markets for the purpose of capital appreciation. The fund invests primarily in common stocks in the financial, consumer goods, information technology, energy, telecommunications, and industrial sectors. The plans’ trustee is required to notify the fund manager 10 days prior to a withdrawal from the fund. The fund manager retains the right to restrict withdrawals from the fund so as not to disadvantage other investors in the fund.
-4	The stated intent of this fund is to invest mainly in equity securities of emerging market companies, or those companies that derive a significant portion of their revenues or profits from emerging economies for the purpose of long-term capital growth. The plans’ trustee is required to notify the fund manager 15 days prior to a withdrawal from the fund as of the last day of any month. The fund reserves the right to suspend and compel withdrawals. The fund also reserves the right to make all or a portion of redemptions in-kind rather than in cash or in a combination of cash and in-kind.
-5	The stated intent of this fund is to invest in a diversified portfolio of international equity securities for the purpose of capital appreciation. The fund invests primarily in common stocks in the consumer goods, financial, health care, materials, energy, and information technology sectors. The plans’ trustee is required to notify the fund manager 10 days prior to a withdrawal from the fund. The fund manager retains the right to restrict withdrawals from the fund so as not to disadvantage other investors in the fund.
-6	The stated intent of this fund is to invest in U.S. Corporate bonds and U.S. Treasury securities. The fund is managed to closely match the characteristics of a long-term corporate bond index fund and seeks to maintain an average credit quality target of A- or above and a maximum 10 percent allocation to BBB rated securities. The fund’s target duration is approximately 20 years. The trustee of the fund reserves the right to delay the processing of deposits or withdrawals in order to ensure that securities transactions will be carried out in an orderly manner.
-7	The weighted-average credit quality rating of the pension assets fixed income security portfolio is investment grade with a weighted-average duration of approximately 6 years for 2014 and 2013.
-8	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 5 years for 2014 and 2013.
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 value 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 funds assets at fair value less liabilities, divided by the number of units outstanding.
The fair value of fixed income securities, except U.S. Treasury notes and bonds, 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 notes and bonds 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, 2014 and 2013. Additionally, there were no transfers or reclassifications of investments between Level 1 and Level 2 from December 2013 to December 2014. 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				Other
	Benefits				Postretirement
					Benefits
	(Millions)
2015	$	100			$	14
2016	107				15
2017	107				15
2018	110				16
2019	117				13
2020-2024	609				70
In 2015, 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 2014, $27 million in 2013, and $25 million in 2012. The increase in expense 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, 2014
Inventory, Net [Abstract]
Inventories [Text Block]	Note 10 – Inventories
		December 31,
		2014		2013
		(Millions)
	Natural gas liquids, olefins, and natural gas in underground storage	$	150	$	111
	Materials, supplies, and other	81		83
		$	231	$	194

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment [Text Block]	Note 11 – Property, Plant, and Equipment
		Estimated		Depreciation	December 31,
		Useful Life  (1)		Rates (1)
		(Years)		(%)	2014			2013
					(Millions)
	Nonregulated:
	Natural gas gathering and processing facilities	May-40			$	18,749		$	9,185
	Construction in progress	Not applicable			2,648			3,123
	Other	3 - 45			1,850			1,316
	Regulated:
	Natural gas transmission facilities			1.20 - 6.97	10,867			10,633
	Construction in progress			Not applicable	985			273
	Other			1.35 - 33.33	1,336			1,293
	Total property, plant, and equipment, at cost				36,435			25,823
	Accumulated depreciation and amortization				(8,354		)	(7,613		)
	Property, plant, and equipment — net				$	28,081		$	18,210
	__________
	-1	Estimated useful life and depreciation rates are presented as of December 31, 2014. Depreciation rates for regulated assets are prescribed by the FERC.
	Depreciation and amortization expense for Property, plant, and equipment – net was $967 million in 2014, $752 million in 2013, and $712 million in 2012.
	Regulated Property, plant, and equipment – net includes approximately $746 million and $785 million at December 31, 2014 and 2013, 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 $791 million and $497 million are included in Other noncurrent liabilities with the remaining current portion in Accrued liabilities at December 31, 2014 and 2013, respectively.
		December 31,
		2014			2013
		(Millions)
	Beginning balance	$	561		$	579
	Liabilities incurred	101			8
	Liabilities settled (1)	(21		)	(31		)
	Accretion expense	44			53
	Revisions (2)	146			(48		)
	Ending balance	$	831		$	561
	______________
	-1	For 2014 and 2013 liabilities settled include $7 million and $25 million, respectively, 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 life of the assets. 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 2013 revision primarily reflects increases in the estimated remaining useful life of the assets. The 2013 revision also includes an increase of $9 million related to changes in the timing and method of abandonment on certain of Transco’s natural gas storage caverns that were associated with a leak in 2010.
	Transco is entitled to collect in rates the amounts necessary to fund its ARO. All funds received for such retirements 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_

Goodwill and Other Intangible assets Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2014
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		Access Midstream			Total
		(Millions)
	December 31, 2013	$	646	$	—		$	646
	Acquisition	—		474			474
	December 31, 2014	$	646	$	474		$	1,120
	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, 2013, and 2012. Following a significant decline in energy commodity prices and a decline in the fair value of ACMP's publicly-traded limited partner units, both in the fourth quarter of 2014, we performed an additional impairment evaluation as of December 31, 2014 of the goodwill recorded within the Access Midstream segment. In this evaluation, our estimate of the fair value of each reporting unit exceeded its carrying value and thus no impairment losses were recognized in 2014.
	Other Intangible Assets
	The gross carrying amount and accumulated amortization of Other intangible assets – net of accumulated amortization at December 31 are as follows:
		2014					2013
		Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
		(Millions)
	Contractual customer relationships	$	10,763	$	(310	)	$	1,749	$	(105	)
	Other intangible assets – net of accumulated amortization primarily relate to gas gathering, processing, and fractionation contractual customer relationships recognized in the ACMP, Laser, and Caiman acquisitions (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, Laser, and Caiman acquisitions were approximately 17 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 $209 million, $60 million, and $43 million in 2014, 2013, and 2012, respectively. The estimated amortization expense for each of the next five succeeding fiscal years is approximately $357 million.

Accrued_Liabilities

Accrued Liabilities	12 Months Ended
	Dec. 31, 2014
Accrued Liabilities, Current [Abstract]
Accrued Liabilities [Text Block]	Note 13 – Accrued Liabilities
		December 31,
		2014		2013
		(Millions)
	Interest on debt	$	268	$	167
	Employee costs	167		127
	Deferred income	82		47
	Estimated rate refund liability	1		98
	Asset retirement obligations	40		64
	Other, including other loss contingencies	342		294
		$	900	$	797

Debt_Banking_Arrangements_and_

Debt, Banking Arrangements, and Leases	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	Note 14 – Debt, Banking Arrangements, and Leases
	Long-Term Debt
		December 31,
		2014			2013
		(Millions)
	Unsecured:
	Transco:
	6.4% Notes due 2016	$	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
	Pre-merger WPZ:
	3.8% Notes due 2015 (3)	750			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
	3.35% Notes due 2022	750			750
	4.5% Notes due 2023	600			600
	4.3% Notes due 2024	1,000			—
	3.9% Notes due 2025	750			—
	6.3% Notes due 2040	1,250			1,250
	5.8% Notes due 2043	400			400
	5.4% Notes due 2044	500			—
	4.9% Notes due 2045	500			—
	ACMP (1):
	5.875% Notes due 2021	750			—
	6.125% Notes due 2022	750			—
	4.875% Notes due 2023	1,400			—
	4.875% Notes due 2024	750			—
	Credit facility loans	640			—
	The Williams Companies, Inc. (WMB):
	7.875% Notes due 2021	371			371
	3.7% Notes due 2023	850			850
	4.55% Notes due 2024	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			—
	Various — 5.5% to 10.25% Notes and Debentures due 2019 to 2033	55			55
	Credit facility loans	370			—
	Capital lease obligations	5			1
	Net unamortized debt premium (discount) (2)	187			(37		)
	Total long-term debt, including current portion	20,892			11,354
	Long-term debt due within one year	(4		)	(1		)
	Long-term debt	$	20,888		$	11,353
	________________
	(1) See Note 2 – Acquisitions.
	(2) Includes premium related to the fair value of ACMP debt. See Note 2 – Acquisitions.
	(3) Presented as long-term debt due to the merged partnership’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) and capital lease obligations, for each of the next five years:
		December 31, 2014
		(Millions)
	2015	$	—
	2016	375
	2017	785
2018	1,510
2019	32
Issuances and retirements
The merged partnership 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.
On November 15, 2013, Pre-merger WPZ completed a public offering of $600 million of 4.5 percent senior unsecured notes due 2023 and $400 million of 5.8 percent senior unsecured notes due 2043. 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, 2014
	Available			Outstanding
	(Millions)
Pre-merger WPZ credit facility (1)(3)
Loans	$	2,500		$	—
Letters of credit sub-limit	1,300			—
Letters of credit under certain bilateral bank agreements				1
ACMP credit facility (2)
Loans	1,750			640
Letters of credit sub-limit	200			2
Swing line advances sub-limit	100			—
WMB credit facility (1)
Loans	1,500			370
Letters of credit sub-limit	700			—
Letters of credit under certain bilateral bank agreements				15
________________
(1) Under certain conditions, the amount available may be increased up to an additional $500 million.
(2) Under certain conditions, the amount available may be increased up to an additional $250 million.
(3) 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.
The agreements governing the credit facilities contain these terms and conditions:
•	Various covenants may limit, among other things, a borrower’s and its material subsidiaries’ ability to grant certain liens supporting indebtedness, a borrower’s ability to 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.
•	Each time funds were borrowed under Pre-merger WPZ’s credit facilities, the applicable borrower could 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 applicable borrower was required to pay a commitment fee based on the unused portion of its respective credit facility. The applicable margin and the commitment fee were determined for each borrower by reference to a pricing schedule based on such borrower’s senior unsecured long-term debt ratings.
•	Each time funds were borrowed under ACMP’s credit facility, ACMP may choose from two methods of calculating interest: (1) the greater of (a) the reference rate of Wells Fargo Bank, NA, (b) the federal funds effective rate plus 0.50 percent or (c) the Eurodollar rate which is based on LIBOR plus 1.00 percent, each of which is subject to a margin that varies from 0.50 percent to 1.50 percent, according to ACMP’s leverage ratio (as defined in the agreement), or (2) the Eurodollar rate plus a margin that varies from 1.50 percent to 2.50 percent, according to ACMP’s leverage ratio. The revolving credit facility is secured by all of ACMP’s assets. If ACMP reaches investment grade status, ACMP will have the option to release the security under the credit facility and amounts borrowed will bear interest under a specified ratings-based pricing grid. ACMP is required to pay a commitment fee based on the unused portion of its respective credit facility of (a) 0.25 percent to 0.375 percent while it is subject to the leverage-based pricing grid, according to its leverage ratio and (b) 0.15 percent to 0.30 percent while it is subject to the ratings-based pricing grid, according to its senior unsecured long-term debt ratings.
WMB credit facility
On June 27, 2014, we entered into Amendment No. 1 to the First Amended & Restated Credit Agreement, dated as of July 31, 2013. The amendment changed certain defined terms and provisions concerning the maintenance of ownership of the general partner of WPZ and the indebtedness of certain of our subsidiaries that act as general partner of WPZ and of ACMP and increased our permitted financial covenant thresholds.
On February 2, 2015, we entered into the Second Amended and Restated Credit Agreement. The aggregate commitments available remain 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 is extended to February 2, 2020. However, we may request an extension of the maturity date for an additional one year period, up to two times, 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 decreases the letters of credit commitments to $675 million.
Our 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, 2014. At February 24, 2015, we have no borrowings outstanding under our credit facility.
Pre-merger WPZ credit facility
On December 1, 2014, Pre-merger WPZ, Transco, and Northwest Pipeline entered into Amendment No.1 and Consent to the First Amended & Restated Credit Agreement, dated as of July 31, 2013. The amendment provided the consent of the lenders for this credit agreement to continue for ACMP upon consummation of the Merger and the termination of ACMP’s existing credit agreement. In addition, the amendment provided the consent that certain existing liens and guarantees of indebtedness of ACMP to be terminated in connection with the Merger would not become liens and guarantees of indebtedness under this credit agreement.
On February 2, 2015, the Pre-merger WPZ credit facility was terminated in connection with the Merger.
ACMP credit facility
On February 2, 2015, the ACMP credit facility loans outstanding were paid and terminated in connection with the Merger.
Credit facilities for the merged partnership
On February 2, 2015, the merged partnership, 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 an extension of the maturity date for an additional one year period, up to two times to allow a maturity date as late as February 2, 2022, under certain circumstances. The agreement allows for swingline 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.
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, a borrower’s ability to 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 swingline 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 ½ 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 require:
•	The ratio of debt to EBITDA (each as defined in the credit facility) to 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.
•	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.
On February 3, 2015, the merged partnership entered into a Credit Agreement providing for a $1.5 billion short-term credit facility with a maturity date of August 3, 2015 with an option to extend the maturity date to February 2, 2016 subject to certain circumstances.  The short-term credit facility has substantially the same covenants as our $3.5 billion credit facility.  Under our short-term credit facility any time funds are borrowed, the merged partnership must choose whether such borrowing will be an alternate base rate borrowing or a Eurodollar borrowing.  Interest is calculated on each of these types of borrowings in the same manner as under the $3.5 billion credit facility. The merged partnership is required to pay a commitment fee based on the unused portion of the short-term credit facility. The applicable margin and the commitment fee are determined by reference to a pricing schedule based on our senior unsecured long-term debt ratings.
The merged partnership is in compliance with these financial covenants as measured at December 31, 2014.
As of February 24, 2015, $1.3 billion is outstanding under the long-term credit facility.
Commercial Paper Program
Pre-merger WPZ’s commercial paper program allows a maximum outstanding amount at any time of $2 billion of unsecured commercial paper notes. 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 Pre-merger WPZ’s commercial paper outstanding in Current liabilities in the Consolidated Balance Sheet, as the outstanding notes at December 31, 2014 and December 31, 2013, having maturity dates less than three months from the date of issuance. At December 31, 2014, Pre-merger WPZ had $798 million in Commercial paper outstanding at a weighted average interest rate of 0.92 percent and at December 31, 2013, Pre-merger WPZ had $225 million in Commercial paper outstanding at a weighted average interest rate of 0.42 percent.
On February 2, 2015, the merged partnership amended and restated the commercial paper program to allow a maximum outstanding of $3 billion of unsecured commercial paper notes. As of February 24, 2015, $1.8 billion is outstanding under this program.
Cash Payments for Interest (Net of Amounts Capitalized)
Cash payments for interest (net of amounts capitalized) were $681 million in 2014, $472 million in 2013, and $479 million in 2012.
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, 2014, substantially all of these restricted net assets relate to the net assets of Pre-merger WPZ and ACMP, which are technically considered restricted under this accounting rule due to terms within WPZ’s and ACMP’s partnership agreements that govern the partnerships’ assets. Our interest in Pre-merger WPZ’s and ACMP’s net assets that are considered to be restricted at December 31, 2014 was $15 billion.
Leases-Lessee
The future minimum annual rentals under noncancelable operating leases, are payable as follows:
	December 31, 2014
	(Millions)
2015	$	83
2016	71
2017	55
2018	41
2019	33
Thereafter	129
Total	$	412
Total rent expense was $109 million in 2014, $58 million in 2013, and $56 million in 2012 and primarily included in Operating and maintenance expenses and Selling, general, and administrative expenses in the Consolidated Statement of Income.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2014
Stockholders' Equity Note [Abstract]
Stockholders' Equity [Text Block]	Note 15 – Stockholders' Equity
	Cash dividends declared per common share were $1.9575, $1.4375 and $1.19625 for 2014, 2013, and 2012, 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.)
	Our Stockholder Rights Plan expired in September 2014 and no actions were taken to extend the plan.
	AOCI
	The following table presents the changes in AOCI by component, net of income taxes:
		Cash				Foreign			Pension and			Total
		Flow				Currency			Other Post
		Hedges				Translation			Retirement
									Benefits
		(Millions)
	Balance at December 31, 2013	$	(1	)		$	128		$	(291	)	$	(164	)
	Other comprehensive income (loss) before reclassifications	—				(77		)	(101		)	(178		)
	Amounts reclassified from accumulated other comprehensive income (loss)	—				—			21			21
	Other comprehensive income (loss)	—				(77		)	(80		)	(157		)
	Changes in ownership of consolidated subsidiaries, net	—				(20		)	—			(20		)
	Balance at December 31, 2014	$	(1	)		$	31		$	(371	)	$	(341	)
	Reclassifications out of AOCI are presented in the following table by component for the year ended December 31, 2014:
	Component		Reclassifications				Classification
			(Millions)
	Pension and other postretirement benefits:
	Amortization of prior service cost (credit) included in net periodic benefit cost		$	(8	)		Note 9 – Employee Benefit Plans
	Amortization of actuarial (gain) loss included in net periodic benefit cost		41				Note 9 – Employee Benefit Plans
	Total pension and other postretirement benefits, before income taxes		33
	Income tax benefit		(12		)		Provision (benefit) for income taxes
	Reclassifications during the period		$	21

EquityBased_Compensation

Equity-Based Compensation	12 Months Ended
	Dec. 31, 2014
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, 2014, 31 million shares of our common stock were reserved for issuance pursuant to existing and future stock awards, of which 22 million shares were available for future grants.
	Additionally, on May 17, 2007, our stockholders approved an Employee Stock Purchase Plan (ESPP) which authorizes 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 2007 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 193 thousand shares at an average price of $35.33 per share during 2014. Approximately 1.8 million shares were available for purchase under the ESPP at December 31, 2014.
	Operating and maintenance expenses and Selling, general and administrative expenses include equity-based compensation expense for the years ended December 31, 2014, 2013, and 2012 of $44 million, $37 million, and $36 million, respectively. Income tax benefit recognized related to the stock-based compensation expense for the years ended December 31, 2014, 2013, and 2012 was $17 million, $14 million, and $13 million, respectively. Measured but unrecognized stock-based compensation expense at December 31, 2014, was $63 million, which does not include the effect of estimated forfeitures of $2 million. This amount is comprised of $4 million related to stock options and $59 million related to restricted stock units. These amounts are expected to be recognized over a weighted-average period of 2.0 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, 2014:
	Stock Options	Options			Weighted-				Aggregate
					Average				Intrinsic
					Exercise				Value
					Price
		(Millions)							(Millions)
	Outstanding at December 31, 2013	6.7			$	21.82
	Granted	0.8			$	41.76
	Exercised	(1.7	)		$	17.93
	Outstanding at December 31, 2014	5.8			$	25.86			$	110
	Exercisable at December 31, 2014	4			$	21.25			$	96
	The following table summarizes additional information related to stock option activity during each of the last three years:
		Years Ended December 31,
		2014				2013				2012
		(Millions)
	Total intrinsic value of options exercised	$	48			$	23			$	69
	Tax benefits realized on options exercised	$	18			$	9			$	25
	Cash received from the exercise of options	$	31			$	13			$	50
	The weighted-average remaining contractual life for stock options outstanding and exercisable at December 31, 2014, was 5.4 years and 4.2 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:
		2014				2013				2012
	Weighted-average grant date fair value of options for our common stock granted during the year, per share	$	7.5			$	5.94			$	5.65
	Weighted-average assumptions:
	Dividend yield	4.2		%		4.3		%		3.7		%
	Volatility	28		%		29.7		%		30		%
	Risk-free interest rate	2.2		%		1.4		%		1.3		%
	Expected life (years)	6.5				6.5				6.5
	The 2014 expected dividend yield is based on the 2014 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, 2014.
	Restricted Stock Units Outstanding	Shares			Weighted-
					Average
					Fair Value (1)
		(Millions)
	Nonvested at December 31, 2013	3.5			$	27.16
	Granted	1.4			$	42.79
	Forfeited	(0.1	)		$	29.57
	Vested	(1.2	)		$	24.07
	Nonvested at December 31, 2014	3.6			$	33.9
	______________
	-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 or the grant-date market price less dividends projected to be paid over the vesting period. Restricted stock units generally vest after three years.
	Value of Restricted Stock Units	2014				2013				2012
	Weighted-average grant date fair value of restricted stock units granted during the year, per share	$	42.79			$	30.43			$	20.61
	Total fair value of restricted stock units vested during the year ($’s in millions)	$	27			$	27			$	22
	Performance-based restricted stock units granted under the Plan represent 39 percent of nonvested restricted stock units outstanding at December 31, 2014. 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.
	ACMP Plan Information
	Certain employees of ACMP’s general partner received equity-based compensation through ACMP’s equity-based compensation programs. The fair value of the awards issued was determined based on the fair market value of the units of ACMP 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. Beginning in 2015 certain of these employees will transition to our equity-based compensation plans. No additional awards of units through ACMP’s equity-based compensation programs are expected. Included in Operating and maintenance expenses; Selling, general, and administrative expenses; and Equity earnings (losses) is equity-based compensation expense of $11 million related to ACMP’s equity-based compensation program. As of December 31, 2014, there was $65 million of unrecognized compensation expense attributable to the outstanding awards, which does not include the effect of estimated forfeitures of $6 million. These amounts are expected to be recognized over a weighted average period of 2.3 years.
	The following summary reflects nonvested ACMP restricted stock unit activity and related information for the six months ended December 31, 2014:
	Restricted Stock Units Outstanding	Units			Weighted-
					Average
					Fair Value
		(Millions)
	Granted	1.3			$	59.67
	Forfeited	—			$	63.89
	Vested	—			$	63.75
	Nonvested at December 31, 2014	1.3			$	59.35

Fair_Value_Measurements_Guaran

Fair Value Measurements Guarantees and Concentration of Credit Risk	12 Months Ended
	Dec. 31, 2014
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			Fair			Quoted		Significant			Significant
		Amount			Value			Prices In		Other			Unobservable
								Active		Observable			Inputs
								Markets for		Inputs			(Level 3)
								Identical		(Level 2)
								Assets
								(Level 1)
		(Millions)
	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)	(20,887		)	(21,131		)	—		(21,131		)	—
	Guarantee	(31		)	(27		)	—		(27		)	—
	Assets (liabilities) at December 31, 2013:
	Measured on a recurring basis:
	ARO Trust investments	$	33		$	33		$	33	$	—		$	—
	Energy derivatives assets not designated as hedging instruments	3			3			—		—			3
	Energy derivatives liabilities not designated as hedging instruments	(3		)	(3		)	—		(1		)	(2		)
	Additional disclosures:
	Notes receivable and other	77			140			1		6			133
	Long-term debt, including current portion (1)	(11,353		)	(11,971		)	—		(11,971		)	—
	Guarantee	(32		)	(29		)	—		(29		)	—
	________________
	(1) Excludes capital 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 (ARO 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, 2014 or 2013.
	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 $53 million at December 31, 2014. The carrying value of this receivable is $25 million at December 31, 2014. The current and noncurrent portions are reported in Accounts and notes receivable, net and Regulatory assets, deferred charges, and other, respectively, in the Consolidated Balance Sheet.
	At December 31, 2013, notes receivable and other also included a receivable from our former affiliate, WPX, related to various proceedings involving prices charged for power in California and other western states (see Note 18 – Contingent Liabilities and Commitments). In second quarter 2014, the proceedings related to this receivable were settled, and we received $42 million and recorded pretax Income (loss) from discontinued operations of $7 million.
	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. This guarantee is reported in Accrued liabilities in the Consolidated Balance Sheet.
	Assets and liabilities measured at fair value on a nonrecurring basis
	During 2014, we designated certain equipment within our Williams Partners segment as held for sale. The estimated fair value (less cost to sell) of the equipment at December 31, 2014, is $32 million and is 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 information related to sales of similar pre-owned equipment in the principal market. This analysis resulted in impairment charges of $27 million, recorded in Other (income) expense – net within Costs and expenses. This nonrecurring fair value measurement fell within Level 3 of the fair value hierarchy.
	In December 2014, certain materials and equipment within our Access Midstream segment was designated as held for sale. The estimated fair value (less cost to sell) of the equipment at December 31, 2014, is $1 million and is 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 information related to sales of similar pre-owned equipment in the principal market. This analysis resulted in an impairment charge of $12 million, which is included in Other (income) expense – net within Costs and expenses. This nonrecurring fair value measurement fell within Level 3 of the fair value hierarchy.
	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 exposure is approximately $34 million at December 31, 2014. Our exposure declines systematically throughout the remaining term of WilTel’s obligation.
	We have provided guarantees in the event of nonpayment by our previously owned subsidiary, WPX, on certain contracts, primarily a natural gas purchase contract extending through 2023. We estimate the maximum undiscounted potential future payment obligation under these remaining guarantees is approximately $44 million at December 31, 2014. Our recorded liability for these guarantees, which considers our estimate of the fair value of the guarantees, is insignificant.
	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,
		2014			2013
		(Millions)
	NGLs, natural gas, and related products and services	$	730		$	341
	Transportation of natural gas and related products	175			193
	Income tax receivable	167			74
	Other	67			66
	Total	$	1,139		$	674
	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. On December 31, 2014, one customer accounted for $308 million of the consolidated Accounts and notes receivable balance.
Revenues
In 2014, 2013, and 2012, we had one customer in our Williams Partners segment that accounted for 5 percent, 9 percent and 14 percent of our consolidated revenues, respectively. In 2014 we also had a customer, primarily within our Access Midstream segment, that accounted for 9 percent of our consolidated revenues.

Contingent_Liabilities_and_Com

Contingent Liabilities and Commitments	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Contingent Liabilities [Text Block]	Note 18 – Contingent Liabilities and Commitments
	Indemnification of WPX
	We have agreed to indemnify our former affiliate, WPX and its subsidiaries, related to the following matter.
	Reporting of natural gas-related information to trade publications
	Direct and indirect purchasers of natural gas in various states filed class actions against WPX 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.
	In 2011, the Nevada district court granted WPX’s joint motions for summary judgment to preclude the plaintiffs’ state law claims because the federal Natural Gas Act gives the FERC exclusive jurisdiction to resolve those issues. The court also denied the plaintiffs’ class certification motion as moot. The plaintiffs appealed the court’s ruling and on April 10, 2013, the Ninth Circuit Court of Appeals reversed the district court and remanded the cases to the district court to permit the plaintiffs to pursue their state antitrust claims for natural gas sales that were not subject to FERC jurisdiction under the Natural Gas Act. On July 1, 2014, the U.S. Supreme Court agreed to hear the cases. 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 exposures at this time. However, it is reasonably possible that the ultimate resolution of these items 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 an indirect exposure to future developments in this matter.
	Other Legal Matters
	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 June 28, 2013, the Louisiana Department of Environmental Quality (LDEQ) issued a Consolidated Compliance Order & Notice of Potential Penalty that consolidates claims of unpermitted emissions and other deviations under the Clean Air Act that the parties had been negotiating since 2010 and alleged unpermitted emissions arising from the Geismar Incident. On November 12, 2014, the LDEQ issued a Notice of Potential Penalty for the alleged violations. LDEQ then issued a Penalty Assessment on November 21, 2014. We paid a penalty of $194,306 on December 1, 2014.
	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 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.
	On December 11, 2013, the Occupational Safety and Health Administration (OSHA) issued citations in connection with its investigation of the June 13, 2013 incident, which included a Notice of Penalty for $99,000. We settled the citations with OSHA on September 12, 2014 for a penalty of $36,000. The settlement was judicially approved on September 23, 2014 and the order approving settlement became a final order on November 10, 2014. On June 25, 2013, OSHA commenced a second inspection pursuant to its Refinery and Chemical National Emphasis Program (NEP). OSHA did not issue a citation in connection with this NEP inspection and there is a six month statute of limitations for violation of the Occupational Safety and Health Act of 1970 or regulations promulgated under such act.
	Additionally, multiple lawsuits, including class actions for alleged offsite impacts, property damage, customer claims, and personal injury, have been filed against various of our subsidiaries.
	Due to ongoing litigation concerning defenses to liability and limited information as to the nature and extent of plaintiffs’ damages, we cannot reasonably estimate a range of potential loss related to these contingencies at this time.
	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 have 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 November 5, 2013, the court ruled that the applicable statute of limitations bars all FHRA’s claims against us and dismissed those claims with prejudice. FHRA asked the court to reconsider and clarify its ruling. On July 8, 2014, the court reaffirmed its dismissal of all FHRA’s claims and entered judgment for us. On August 6, 2014, FHRA appealed the court’s decision to the Alaska Supreme Court.
	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 November 26, 2014, the City of North Pole (North Pole) filed suit in Alaska state court in Fairbanks against FHRA and WAPI, alleging nuisance and violations of municipal and state statutes based upon the sulfolane contamination allegedly emanating from the North Pole refinery. North Pole claims an unspecified amount of past and future damages as well as punitive damages against WAPI. On December 29, 2014, we filed a motion to dismiss all claims against WAPI based upon North Pole’s failure to timely file suit.
	Independent of the litigation matter described in the preceding paragraphs, in 2013, the Alaska Department of Environmental Conservation (ADEC) 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. On March 6, 2014, the State of Alaska filed suit against FHRA and us in state court in Fairbanks seeking injunctive relief and damages in connection with the sulfolane contamination. On May 5, 2014, FHRA filed cross-claims against us in the State of Alaska suit, and FHRA also seeks injunctive relief and damages. 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.
	Royalty matters
	Certain of ACMP’s customers, including one of its major customers, have been named in various lawsuits alleging underpayment of royalty. In certain of these cases, ACMP has also been named as a defendant based on allegations that it 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 ACMP and its major customer and calculations of the major customer’s royalty payments. We believe that the claims asserted to date are subject to indemnity obligations owed to ACMP 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, 2014, we have accrued liabilities totaling $44 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 ground level ozone, one hour nitrogen dioxide emission limits, and new air quality standards impacting storage vessels, pressure valves, and compressors. We are unable to estimate the costs of asset additions or modifications necessary to comply with these new regulations due to uncertainty created by the various legal challenges to these regulations and the need for further specific regulatory guidance.
	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, 2014, we have accrued liabilities of $11 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, 2014, we have accrued liabilities totaling $8 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, 2014, 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, 2014, 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 $689 million at December 31, 2014.

Segment_Disclosures

Segment Disclosures	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Disclosures [Text Block]	Note 19 – Segment Disclosures
	Our reportable segments are Williams Partners, Access Midstream, and Williams NGL & Petchem Services. All remaining business activities are included in Other. (See Note 1 – Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies.)
	Our segment presentations of Williams Partners and Access Midstream are 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 structures. These partnerships maintain capital and cash management structures that are separate from ours. They are self-funding and maintain their 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 these entities as a whole.
	Performance Measurement
	We currently evaluate segment operating performance based upon Segment profit (loss) from operations, which includes Segment revenues from external and internal customers, segment costs and expenses, Equity earnings (losses), Gain on remeasurement of equity-method investment, and Income (loss) from investments. General corporate expenses represent Selling, general, and administrative expenses that are not allocated to our segments. The accounting policies of the segments are the same as those described in Note 1 – Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies. Intersegment revenues are generally accounted for at current market prices as if the sales were to unaffiliated third parties.
	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:
		2014	$	7,229		$	408		$	7,637
		2013		6,703			157			6,860
		2012		7,335			151			7,486
	Long-lived assets:
		2014	$	38,290		$	1,364		$	39,654
		2013		19,260			1,240			20,500
		2012		16,940			880			17,820
	Long-lived assets are comprised of property, plant, and equipment, goodwill, and other intangible assets.
	The following table reflects the reconciliation of Segment revenues and Segment profit (loss) to Total revenues and Operating income (loss) as reported in the Consolidated Statement of Income and Other financial information related to Long-lived assets.
		Williams				Access				Williams			Other			Eliminations			Total
		Partners				Midstream				NGL & Petchem
										Services
		(Millions)
	2014
	Segment revenues:
	Service revenues
	External	$	3,106			$	781			$	—		$	229		$	—		$	4,116
	Internal	1				—				—			30			(31		)	—
	Total service revenues	3,107				781				—			259			(31		)	4,116
	Product sales
	External	3,521				—				—			—			—			3,521
	Internal	—				—				—			—			—			—
	Total product sales	3,521				—				—			—			—			3,521
	Total revenues	$	6,628			$	781			$	—		$	259		$	(31	)	$	7,637
	Segment profit (loss)	$	1,743			$	2,803			$	(115	)	$	4					$	4,435
	Less:
	Equity earnings (losses)	132				90				(78		)	—						144
	Gain on remeasurement of equity-method investment	—				2,544				—			—						2,544
	Income (loss) from investments	—				1				(1		)	—						—
	Segment operating income (loss)	$	1,611			$	168			$	(36	)	$	4					1,747
	General corporate expenses																		(178		)
	Operating income (loss)																		$	1,569
	Other financial information:
	Additions to long-lived assets (1)	$	3,449			$	16,964			$	291		$	54		$	(2	)	$	20,756
	Depreciation and amortization	855				296				—			25						1,176
	__________________
	(1) 2014 Additions to long-lived assets within our Access Midstream segment primarily includes the acquisition-date fair value of long-lived assets from the ACMP Acquisition (see Note 2 - Acquisitions).
	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
	Segment profit (loss)	$	1,677			$	61			$	(32	)	$	(5	)				$	1,701
	Less:
	Equity earnings (losses)	104				30				—			—						134
	Income (loss) from investments	(3		)		31				—			—						28
	Segment operating income (loss)	$	1,576			$	—			$	(32	)	$	(5	)				1,539
	General corporate expenses																		(164		)
	Operating income (loss)																		$	1,375
Other financial information:
Additions to long-lived assets	$	3,409			$	—			$	295		$	27					$	3,731
Depreciation and amortization	791				—				—			24						815
	Williams				Access				Williams			Other			Eliminations			Total
	Partners				Midstream				NGL & Petchem
									Services
	(Millions)
2012
Segment revenues:
Service revenues
External	$	2,714			$	—			$	—		$	15		$	—		$	2,729
Internal	—				—				—			12			(12		)	—
Total service revenues	2,714				—				—			27			(12		)	2,729
Product sales
External	4,757				—				—			—			—			4,757
Internal	—				—				—			—			—			—
Total product sales	4,757				—				—			—			—			4,757
Total revenues	$	7,471			$	—			$	—		$	27		$	(12	)	$	7,486
Segment profit (loss)	$	1,907			$	—			$	(3	)	$	56					$	1,960
Less:
Equity earnings (losses)	111				—				—			—						111
Income (loss) from investments	(4		)		—				—			53						49
Segment operating income (loss)	$	1,800			$	—			$	(3	)	$	3					1,800
General corporate expenses																		(188		)
Operating income (loss)																		$	1,612
Other financial information:
Additions to long-lived assets	$	5,851			$	—			$	136		$	31					$	6,018
Depreciation and amortization	734				—				—			22						756
The following table reflects Total assets and Equity-method investments by reportable segments:
		Total Assets								Equity-Method Investments
		31-Dec-14				31-Dec-13				31-Dec-14			31-Dec-13
		(Millions)
Williams Partners		$	26,298			$	23,571			$	2,395		$	2,187
Access Midstream		23,024				2,161				6,004			2,161
Williams NGL & Petchem Services		612				486				—			12
Other		1,220				1,359				1			—
Eliminations		(591		)		(435		)		—			—
Total		$	50,563			$	27,142			$	8,400		$	4,360

Subsequent_Events_Notes

Subsequent Events (Notes)	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent Events [Text Block]	Note 20 – Subsequent Events (Unaudited)
	On February 2, 2015, we completed the Merger of our consolidated master limited partnerships, Pre-merger WPZ and ACMP. (See Note 1 – Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies.)

Schedule_I_Condensed_Financial

Schedule I Condensed Financial Information Of Parent Company Only	12 Months Ended
	Dec. 31, 2014
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,
		2014			2013			2012
		(Millions, except per-share amounts)
	Equity in earnings of consolidated subsidiaries	$	1,799		$	1,564		$	1,895
	Equity earnings (losses) from investment in Access Midstream Partners	(7		)	30			—
	Interest incurred — external	(206		)	(156		)	(128		)
	Interest incurred — affiliate	(797		)	(722		)	(816		)
	Interest income — affiliate	10			71			84
	Gain on remeasurement of equity-method investment	2,544			—			—
	Other income (expense) — net	(13		)	32			3
	Income from continuing operations before income taxes	3,330			819			1,038
	Provision for income taxes	1,220			378			315
	Income (loss) from continuing operations	2,110			441			723
	Income (loss) from discontinued operations	4			(11		)	136
	Net income (loss)	$	2,114		$	430		$	859
	Basic earnings (loss) per common share:
	Income (loss) from continuing operations	$	2.93		$	0.65		$	1.17
	Income (loss) from discontinued operations	0.01			(.02		)	0.22
	Net income (loss)	$	2.94		$	0.63		$	1.39
	Weighted-average shares (thousands)	719,325			682,948			619,792
	Diluted earnings (loss) per common share:
	Income (loss) from continuing operations	2.91			0.64			$	1.15
	Income (loss) from discontinued operations	0.01			(.02		)	0.22
	Net income (loss)	$	2.92		$	0.62		$	1.37
	Weighted-average shares (thousands)	723,641			687,185			625,486
	Other comprehensive income (loss):
	Equity in other comprehensive income (loss) of consolidated subsidiaries	$	(96	)	$	(41	)	$	21
	Other comprehensive income (loss) attributable to The Williams Companies, Inc.	(80		)	239			6
	Other comprehensive income (loss)	(176		)	198			27
	Less: Other comprehensive income (loss) attributable to noncontrolling interests	(19		)	—			—
	Comprehensive income (loss) attributable to The Williams Companies, Inc.	$	1,957		$	628		$	886
	See accompanying notes.
	The Williams Companies, Inc.
	Schedule I — Condensed Financial Information of Registrant – (Continued)
	Balance Sheet (Parent)
		December 31,
		2014			2013
		(Millions)
	ASSETS
	Current assets:
	Cash and cash equivalents	$	49		$	282
	Other current assets and deferred charges	246			167
	Total current assets	295			449
	Investments in and advances to consolidated subsidiaries	31,405			19,162
	Investment in Access Midstream Partners	—			2,161
	Property, plant, and, equipment — net	99			68
	Other noncurrent assets	46			34
	Total assets	$	31,845		$	21,874
	LIABILITIES AND STOCKHOLDERS’ EQUITY
	Current liabilities:
	Accounts payable	$	27		$	26
	Long-term debt due within one year	—			1
	Other current liabilities	174			147
	Total current liabilities	201			174
	Long-term debt	4,562			2,296
	Notes payable — affiliates	13,295			10,830
	Pension, other postretirement, and other noncurrent liabilities	409			282
	Deferred income taxes	4,601			3,428
	Contingent liabilities and commitments
	Equity:
	Common stock	782			718
Other stockholders’ equity	7,995			4,146
Total stockholders’ equity	8,777			4,864
Total liabilities and stockholders’ equity	$	31,845		$	21,874
See accompanying notes.
The Williams Companies, Inc.
Schedule I — Condensed Financial Information of Registrant – (Continued)
Statement of Cash Flows (Parent)
	Years Ended December 31,
	2014			2013			2012
	(Millions)
NET CASH FLOWS PROVIDED (USED) BY OPERATING ACTIVITIES	$	(500	)	$	19		$	(11	)
FINANCING ACTIVITIES:
Proceeds from long-term debt	2,935			—			848
Payments of long-term debt	(671		)	(1		)	(28		)
Changes in notes payable to affiliates	2,465			1,892			520
Tax benefit of stock-based awards	25			19			44
Proceeds from issuance of common stock	3,416			18			2,550
Dividends paid	(1,412		)	(982		)	(742		)
Other — net	(17		)	(3		)	(7		)
Net cash provided (used) by financing activities	6,741			943			3,185
INVESTING ACTIVITIES:
Capital expenditures	(54		)	(23		)	(18		)
Purchase of Access Midstream Partners	(5,995		)	—			—
Purchase of investment in Access Midstream Partners	—			(4		)	(2,179		)
Changes in investments in and advances to consolidated subsidiaries	(450		)	(985		)	(953		)
Other — net	25			(8		)	24
Net cash provided (used) by investing activities	(6,474		)	(1,020		)	(3,126		)
Increase (decrease) in cash and cash equivalents	(233		)	(58		)	48
Cash and cash equivalents at beginning of year	282			340			292
Cash and cash equivalents at end of year	$	49		$	282		$	340
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, 2014, is approximately $681 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, 2014, 2013, and 2012 was approximately $1.9 billion, $1.5 billion, and $1.1 billion, respectively.

Schedule_II_Valuation_and_Qual

Schedule II Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts [Abstract]
Schedule II Valuation and Qualifying Accounts [Text Block]
				Additions
		Beginning		Charged			Other		Deductions			Ending
		Balance		(Credited)								Balance
				To Costs and
				Expenses
		(Millions)
	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
	2012
	Allowance for doubtful accounts — accounts and notes receivable (1)	1		—			—		1		(2)	—
	Deferred tax asset valuation allowance (1)	145		(1		)	—		—			144
	_______________________
	(1)    Deducted from related assets.
	(2)    Represents balances written off, reclassifications, and recoveries.

Description_of_Business_Basis_1

Description of Business, Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
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 in entities 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 Income 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 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. 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 postretirement benefits. Our current and noncurrent regulatory asset and liability balances for the years ended December 31, 2014 and 2013 are as follows:
		December 31,
		2014		2013
		(Millions)
	Current assets reported within Other current assets and deferred charges	$	81	$	39
	Noncurrent assets reported within Regulatory assets, deferred charges, and other	337		353
	Total regulated assets	$	418	$	392
	Current liabilities reported within Accrued liabilities	$	11	$	19
	Noncurrent liabilities reported within Other noncurrent liabilities	375		329
	Total regulated liabilities	$	386	$	348
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. (See Note 11 – Property, Plant, and Equipment.)
	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 Income.
	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. 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 Income, except for regulated entities, for which the liability is offset by a regulatory asset as management expects to recover amounts in future rates. 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.
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 Income.
	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 Income. 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 Income 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 Income.
	Certain gains and losses on derivative instruments included in the Consolidated Statement of Income 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.
Revenues [Policy Text Block]	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. The latter is included in Other income (expense) – net below Operating income (loss) in the Consolidated Statement of Income. 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 accumulated other comprehensive income 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.
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 Income 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 Income includes any dilutive effect of stock options, nonvested restricted stock units, and convertible debt, unless otherwise noted. Beginning in 2012, we have unvested service-based restricted stock units that contain a nonforfeitable right to dividends during the vesting period and are considered participating securities. Basic and diluted earnings (loss) per common share are calculated using the two-class method and the treasury-stock method. Whichever method results in the most dilutive earnings (loss) per common share is reported.
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 income 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.
	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 the Consolidated Statement of Income.

Description_of_Business_Basis_2

Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
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, 2014 and 2013 are as follows:
		December 31,
		2014		2013
		(Millions)
	Current assets reported within Other current assets and deferred charges	$	81	$	39
	Noncurrent assets reported within Regulatory assets, deferred charges, and other	337		353
	Total regulated assets	$	418	$	392
	Current liabilities reported within Accrued liabilities	$	11	$	19
	Noncurrent liabilities reported within Other noncurrent liabilities	375		329
	Total regulated liabilities	$	386	$	348

Acquisitions_Tables

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2014
Business Acquisition [Line Items]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The following table presents the preliminary allocation of the acquisition-date fair value of the major classes of the assets acquired, which are presented in the Access Midstream segment, liabilities assumed, and noncontrolling interest at July 1, 2014. The allocation is considered preliminary because the valuation work has not been completed due to the ongoing review of the valuation results and validation of significant inputs and assumptions. Significant changes since the allocation disclosed in the third quarter reflect an increase in investments and decreases in goodwill, other intangible assets, and property, plant and equipment - net, generally associated with the attribution of fair value between consolidated and non-consolidated operations. The fair value of accounts receivable acquired equals contractual amounts receivable.
		(Millions)
	Accounts receivable	$	168
	Other current assets	63
	Investments	5,872
	Property, plant, and equipment - net	7,015
	Goodwill	474
	Other intangible assets	9,009
	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
LaserAndCaimanAcquisitions [Member]
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 net assets, which are included in the Williams Partners segment:
		Laser			Caiman
		(Millions)
	Assets held-for-sale	$	18		$	—
	Other current assets	3			16
	Property, plant, and equipment	158			656
	Intangible assets	318			1,393
	Current liabilities	(21		)	(94		)
	Noncurrent liabilities	—			(3		)
	Identifiable net assets acquired	476			1,968
	Goodwill	290			356
		$	766		$	2,324

Variable_Interest_Entities_Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2014
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,
		2014			2013 (1)			Classification
		(Millions)
	Assets (liabilities):
	Cash and cash equivalents	$	113		$	130		Cash and cash equivalents
	Accounts receivable	52			—			Accounts and notes receivable – net - Trade and other
	Other current assets	3			—			Other current assets and deferred charges
	Property, plant, and equipment – net	2,794			1,113			Property, plant, and equipment – net
	Goodwill	103			—			Goodwill
	Other intangible assets, net	1,493			—			Other intangible assets- net of accumulated amortization
	Other noncurrent assets	14			—			Regulatory assets, deferred charges, and other
	Accounts payable	(48		)	(146		)	Accounts payable
	Accrued liabilities	(36		)	(3		)	Accrued liabilities
	Current deferred revenue	(45		)	(10		)	Accrued liabilities
	Noncurrent deferred income taxes	(13		)	—			Deferred income taxes
	Asset retirement obligation	(94		)	—			Other noncurrent liabilities
	Noncurrent deferred revenue associated with customer advance payments	(395		)	(115		)	Other noncurrent liabilities
	-1	Amounts presented for December 31, 2013, include balances related to Bluegrass Pipeline. See discussion of the subsequent deconsolidation of Bluegrass Pipeline below.

Investing_Activities_Tables

Investing Activities (Tables)	12 Months Ended
	Dec. 31, 2014
Investments [Abstract]
Investing income [Table Text Block]	Investing Income
		Years Ended December 31,
		2014			2013			2012
		(Millions)
	Gain on remeasurement of equity-method investment (1)	$	2,544		$	—		$	—
	Equity earnings (losses) (1)	144			134			111
	Income (loss) from investments (1)	—			28			49
	Interest income and other	43			53			28
	Total investing income	$	2,731		$	215		$	188
	__________
	-1	Items also included in Segment profit (loss). (See Note 19 – Segment Disclosures.)
Investments [Table Text Block]	Investments
		December 31,
		2014			2013
		(Millions)
	Equity method:
	Appalachia Midstream Investments (2)	$	3,033		$	—
	Delaware Basin gas gathering system — 50% (2)	1,478			—
	UEOM — 49% (2)	1,411			—
	Discovery Producer Services LLC (Discovery) — 60% (1)	602			527
	Laurel Mountain — 69% (1)	459			481
	Overland Pass Pipeline Company LLC (OPPL) — 50%	453			452
	Caiman II — 58% (1)	432			256
	Gulfstream — 50%	317			333
	Access Midstream Partners — 24% in 2013	—			2,161
	Other	215			150
		$	8,400		$	4,360
	___________
	-1	We account for these investments under the equity method of accounting due to the significant participatory rights of our partners such that we do not control or are otherwise not the primary beneficiary of the investments.
	-2	We acquired these investments in the ACMP Acquisition. (Note 2 – Acquisitions.) As discussed in Note 1 – Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies, the Appalachia Midstream Investments include investments in 11 different gathering systems in the Marcellus Shale. Ownership interests range from 33.75 percent to 67.50 percent, resulting in an overall approximate average interest of 45 percent. For those investments where we own in excess of 50 percent, we apply the equity-method of accounting due to the significant participation rights of our partners such that we do not control.
Contributions [Table Text Block]
		2014			2013			2012
		(Millions)
	Caiman II	$	175		$	192		$	69
	Discovery	106			193			169
	Appalachia Midstream Investments	84			—			—
	UEOM	57			—			—
	Delaware Basin gas gathering system	20			—			—
	Laurel Mountain	12			42			174
Dividends and distributions [Table Text Block]
		2014			2013			2012
		(Millions)
	Appalachia Midstream Investments	$	120		$	—		$	—
	Gulfstream	81			81			79
	Access Midstream	64			93			—
	Laurel Mountain	39			—			—
	Discovery	36			12			21
	OPPL	27			27			28
	Aux Sable Liquid Products L.P.	15			20			28
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,
		2014			2013
		(Millions)
	Assets (liabilities):
	Current assets	$	599		$	689
	Noncurrent assets	9,135			13,621
	Current liabilities	(850		)	(573		)
	Noncurrent liabilities	(954		)	(4,563		)
	Noncontrolling interest	—			(254		)
		Years Ended December 31,
		2014			2013			2012
		(Millions)
	Gross revenue	$	1,623		$	2,406		$	1,821
	Operating income	534			699			557
	Net income	460			627			488

Other_Income_and_Expense_Table

Other Income and Expense (Tables)	12 Months Ended
	Dec. 31, 2014
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 Income:
		Years Ended December 31,
		2014			2013			2012
		(Millions)
	Williams Partners
	Contingency gain settlement	$	(154	)	$	—		$	—
	Impairment of certain materials and equipment (See Note 17)	40			—			—
	Net gain related to partial acreage dedication release	(12		)	—			—
	Amortization of regulatory assets associated with asset retirement obligations	33			30			7
	Write-off of the Eminence abandonment regulatory asset not recoverable through rates	(3		)	12			—
	Insurance recoveries associated with the Eminence abandonment	—			(16		)	—
	Project feasibility costs	2			4			21
	Capitalization of project feasibility costs previously expensed	(5		)	(1		)	(19		)
	Loss associated with a producer claim	—			25			—
	Access Midstream
	Loss related to sale of certain assets	10			—			—
	Impairment of certain materials and equipment held for sale (See Note 17)	12			—			—
	Williams NGL & Petchem Services
	Write-off of an abandoned project	—			20			—

Provision_Benefit_for_Income_T1

Provision (Benefit) for Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Provision (benefit) for income taxes from continuing operations [Table Text Block]	The Provision (benefit) for income taxes includes:
		Years Ended December 31,
		2014			2013			2012
		(Millions)
	Current:
	Federal	$	(9	)	$	(17	)	$	91
	State	2			7			17
	Foreign	10			(13		)	40
		3			(23		)	148
	Deferred:
	Federal	1,108			348			220
	State	119			40			(13		)
	Foreign	19			36			5
		1,246			424			212
	Total provision (benefit)	$	1,249		$	401		$	360
Provision for income taxes from continuing operations at federal statutory rate [Table Text Block]	Reconciliations from the Provision (benefit) for income taxes at the federal statutory rate to the recorded Provision (benefit) for income taxes are as follows:
		Years Ended December 31,
		2014			2013			2012
		(Millions)
	Provision (benefit) at statutory rate	$	1,255		$	378		$	451
	Increases (decreases) in taxes resulting from:
	Impact of nontaxable noncontrolling interests	(75		)	(78		)	(72		)
	State income taxes (net of federal benefit)	82			26			2
	Foreign operations – net	(11		)	(32		)	(36		)
	Taxes on undistributed earnings of foreign subsidiaries – net	(37		)	99			—
	Other – net	35			8			15
	Provision (benefit) for income taxes	$	1,249		$	401		$	360
Deferred tax liabilities and Deferred tax assets [Table Text Block]	Significant components of deferred tax liabilities and deferred tax assets are as follows:
		December 31,
		2014			2013
		(Millions)
	Deferred tax liabilities:
	Property, plant, and equipment	$	4		$	102
	Undistributed earnings of foreign subsidiaries	—			75
	Investments	5,472			3,663
	Other	10			—
	Total deferred tax liabilities	5,486			3,840
	Deferred tax assets:
	Accrued liabilities	178			126
	Minimum tax credits	137			66
	Foreign tax credit	251			42
	Federal loss carryovers	134			—
	State losses and credits	250			194
	Other	97			91
	Total deferred tax assets	1,047			519
	Less valuation allowance	206			181
	Net deferred tax assets	841			338
	Overall net deferred tax liabilities	$	4,645		$	3,502
Reconciliation of beginning and ending amount of unrecognized tax benefits [Table Bext Block]	A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
		2014			2013
		(Millions)
	Balance at beginning of period	$	66		$	58
	Additions based on tax positions related to the current year	11			4
	Additions for tax positions of prior years	12			18
	Reductions for tax positions of prior years	—			(2		)
	Settlement with taxing authorities	—			(12		)
	Balance at end of period	$	89		$	66

Earnings_Loss_Per_Common_Share1

Earnings (Loss) Per Common Share from Continuing Operations (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings (loss) per common share from continuing operations [Table Text Block]
		Years Ended December 31,
		2014		2013		2012
		(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	$	2,110	$	441	$	723
	Basic weighted-average shares	719,325		682,948		619,792
	Effect of dilutive securities:
	Nonvested restricted stock units	2,234		1,995		2,694
	Stock options	2,064		2,149		2,608
	Convertible debentures	18		93		392
	Diluted weighted-average shares	723,641		687,185		625,486
	Earnings (loss) per common share from continuing operations:
	Basic	$	2.93	$	0.65	$	1.17
	Diluted	$	2.91	$	0.64	$	1.15

Employee_Benefit_Plans_Tables

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2014
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
		2014				2013				2014				2013
		(Millions)
	Change in benefit obligation:
	Benefit obligation at beginning of year	$	1,384			$	1,549			$	213			$	331
	Service cost	40				44				2				2
	Interest cost	62				51				10				11
	Plan participants’ contributions	—				—				2				6
	Benefits paid	(86		)		(87		)		(14		)		(19		)
	Medicare Part D subsidy	—				—				—				4
	Plan amendment	—				—				1				(59		)
	Actuarial loss (gain)	144				(173		)		21				(63		)
	Settlements	(3		)		—				(1		)		—
	Curtailments	—				—				(1		)		—
	Other	3				—				—				—
	Benefit obligation at end of year	1,544				1,384				233				213
	Change in plan assets:
	Fair value of plan assets at beginning of year	1,241				1,071				201				175
	Actual return on plan assets	78				165				13				31
	Employer contributions	63				92				6				8
	Plan participants’ contributions	—				—				2				6
	Benefits paid	(86		)		(87		)		(14		)		(19		)
	Settlements	(3		)		—				—				—
	Fair value of plan assets at end of year	1,293				1,241				208				201
	Funded status — underfunded	$	(251	)		$	(143	)		$	(25	)		$	(12	)
	Accumulated benefit obligation	$	1,516			$	1,359
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,
		2014				2013
		(Millions)
	Underfunded pension plans:
	Current liabilities	$	2			$	1
	Noncurrent liabilities	249				142
	Underfunded other postretirement benefit plans:
	Current liabilities	7				8
	Noncurrent liabilities	18				4
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
		2014				2013				2014				2013
		(Millions)
	Amounts included in Accumulated other comprehensive income (loss):
	Prior service (cost) credit	$	—			$	—			$	17			$	26
	Net actuarial loss	(593		)		(491		)		(28		)		(11		)
	Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline:
	Prior service credit	N/A				N/A				$	30			$	42
	Net actuarial loss	N/A				N/A				(4		)		(2		)
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
		2014				2013				2012				2014				2013			2012
		(Millions)
	Components of net periodic benefit cost:
	Service cost	$	40			$	44			$	39			$	2			$	2		$	3
	Interest cost	62				51				55				10				11			13
	Expected return on plan assets	(76		)		(61		)		(64		)		(12		)		(9		)	(9		)
	Amortization of prior service cost (credit)	—				1				1				(20		)		(12		)	(7		)
	Amortization of net actuarial loss	39				60				53				—				4			8
	Net actuarial loss from settlements and curtailments	1				—				5				(1		)		—			—
	Reclassification to regulatory liability	—				—				—				4				2			—
	Net periodic benefit cost	$	66			$	95			$	89			$	(17	)		$	(2	)	$	8
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
		2014				2013				2012				2014				2013			2012
		(Millions)
	Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss):
	Net actuarial gain (loss)	$	(142	)		$	277			$	(51	)		$	(18	)		$	23		$	2
	Prior service (cost) credit	—				—				—				(1		)		23			2
	Amortization of prior service cost (credit)	—				1				1				(8		)		(4		)	(3		)
	Amortization of net actuarial loss and loss from settlements and curtailments	40				60				58				1				1			3
	Other changes in plan assets and benefit obligations recognized in Other comprehensive income (loss)	$	(102	)		$	338			$	8			$	(26	)		$	43		$	4
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:
			2014				2013				2012
			(Millions)
	Other changes in plan assets and benefit obligations recognized in regulatory (assets) liabilities:
	Net actuarial gain (loss)		$	(2	)		$	62			$	13
	Prior service credit		—				36				4
	Amortization of prior service credit		(12		)		(8		)		(4		)
	Amortization of net actuarial loss		—				3				5
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 2015 are as follows:
		Pension				Other
		Benefits				Postretirement
						Benefits
		(Millions)
	Amounts included in Accumulated other comprehensive income (loss):
	Prior service credit	$	—			$	(7	)
	Net actuarial loss	43				1
	Amounts included in regulatory liabilities associated with Transco and Northwest Pipeline:
	Prior service credit	N/A				$	(10	)
	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
		2014			2013			2014			2013
	Discount rate	3.96	%		4.68	%		4.12	%		4.8	%
	Rate of compensation increase	4.62			4.56			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
		2014			2013			2012			2014			2013			2012
	Discount rate	4.68	%		3.43	%		3.98	%		4.8	%		3.97	%		4.22	%
	Expected long-term rate of return on plan assets	6.85			5.9			6.3			6.11			5.26			5.71
	Rate of compensation increase	4.56			4.57			4.52			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	9				(7		)
Fair values of plan assets [Table Text Block]	The fair values of our pension plan assets at December 31, 2014 and 2013 by asset class are as follows:
		2014
		Quoted Prices				Significant				Significant				Total
		in Active				Other				Unobservable
		Markets for				Observable				Inputs
		Identical				Inputs				(Level 3)
		Assets				(Level 2)
		(Level 1)
		(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
	Commingled investment funds:
	Equities — U.S. large cap (1)	—				189				—				189
	Equities — International small cap (2)	—				24				—				24
	Equities — Emerging markets value (3)	—				27				—				27
	Equities — Emerging markets growth (4)	—				19				—				19
	Equities — International developed markets large cap value (5)	—				101				—				101
	Fixed income — Corporate bonds (6)	—				163				—				163
	Fixed income securities (7):
	U.S. Treasury securities	31				—				—				31
	Mortgage-backed securities	—				65				—				65
	Corporate bonds	—				222				—				222
	Insurance company investment contracts and other	—				7				—				7
	Total assets at fair value at December 31, 2014	$	416			$	877			$	—			$	1,293
		2013
		Quoted Prices				Significant				Significant				Total
		in Active				Other				Unobservable
		Markets for				Observable				Inputs
		Identical				Inputs				(Level 3)
		Assets				(Level 2)
		(Level 1)
		(Millions)
	Pension assets:
	Cash management fund	$	23			$	—			$	—			$	23
	Equity securities:
	U.S. large cap	211				—				—				211
	U.S. small cap	146				—				—				146
	International developed markets large cap growth	—				59				—				59
	Preferred stock	2				—				—				2
	Commingled investment funds:
	Equities — U.S. large cap (1)	—				179				—				179
	Equities — International small cap (2)	—				24				—				24
	Equities — Emerging markets value (3)	—				34				—				34
	Equities — Emerging markets growth (4)	—				19				—				19
	Equities — International developed markets large cap value (5)	—				100				—				100
	Fixed income — Corporate bonds (6)	—				140				—				140
	Fixed income securities (7):
	U.S. Treasury securities	30				—				—				30
	Mortgage-backed securities	—				67				—				67
	Corporate bonds	—				200				—				200
	Insurance company investment contracts and other	—				7				—				7
	Total assets at fair value at December 31, 2013	$	412			$	829			$	—			$	1,241
	The fair values of our other postretirement benefits plan assets at December 31, 2014 and 2013 by asset class are as follows:
		2014
		Quoted Prices				Significant				Significant				Total
		in Active				Other				Unobservable
		Markets for				Observable				Inputs
		Identical				Inputs				(Level 3)
		Assets				(Level 2)
		(Level 1)
	(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
Commingled investment funds:
Equities — U.S. large cap (1)	—				19				—				19
Equities — International small cap (2)	—				2				—				2
Equities — Emerging markets value (3)	—				3				—				3
Equities — Emerging markets growth (4)	—				2				—				2
Equities — International developed markets large cap value (5)	—				10				—				10
Fixed income — Corporate bonds (6)	—				16				—				16
Fixed income securities (8):
U.S. Treasury securities	3				—				—				3
Government and municipal bonds	—				11				—				11
Mortgage-backed securities	—				7				—				7
Corporate bonds	—				23				—				23
Total assets at fair value at December 31, 2014	$	98			$	110			$	—			$	208
	2013
	Quoted Prices				Significant				Significant				Total
	in Active				Other				Unobservable
	Markets for				Observable				Inputs
	Identical				Inputs				(Level 3)
	Assets				(Level 2)
	(Level 1)
	(Millions)
Other postretirement benefit assets:
Cash management funds	$	13			$	—			$	—			$	13
Equity securities:
U.S. large cap	52				—				—				52
U.S. small cap	29				—				—				29
International developed markets large cap growth	—				15				—				15
Emerging markets growth	1				1				—				2
Commingled investment funds:
Equities — U.S. large cap (1)	—				18				—				18
Equities — International small cap (2)	—				2				—				2
Equities — Emerging markets value (3)	—				4				—				4
Equities — Emerging markets growth (4)	—				2				—				2
Equities — International developed markets large cap value (5)	—				10				—				10
Fixed income — Corporate bonds (6)	—				14				—				14
Fixed income securities (8):
U.S. Treasury securities	3				—				—				3
Government and municipal bonds	—				10				—				10
Mortgage-backed securities	—				7				—				7
Corporate bonds	—				20				—				20
Total assets at fair value at December 31, 2013	$	98			$	103			$	—			$	201
____________
-1	The stated intent of this fund is to invest primarily in equity securities comprising the Standard & Poor’s 500 Index. The investment objective of the fund is to approximate the performance of the Standard & Poor’s 500 Index over the long term. The fund manager retains the right to restrict withdrawals from the fund so as not to disadvantage other investors in the fund.
-2	The stated intent of this fund is to invest in equity securities of international small capitalization companies for the purpose of capital appreciation. The fund invests primarily in equity securities of non-U.S. issuers and other Depository Receipts listed on globally recognized exchanges. The fund may also invest up to 15 percent of its net asset value in emerging markets. The plans’ trustee is required to notify the fund manager 10 days prior to a withdrawal from the fund. For any redemption made within 180 days of contribution, the fund reserves the right to charge a 1.5 percent redemption fee. The fund also reserves the right to make all or a portion of redemptions in-kind rather than in cash or in a combination of cash and in-kind.
-3	The stated intent of this fund is to invest in equity securities of international emerging markets for the purpose of capital appreciation. The fund invests primarily in common stocks in the financial, consumer goods, information technology, energy, telecommunications, and industrial sectors. The plans’ trustee is required to notify the fund manager 10 days prior to a withdrawal from the fund. The fund manager retains the right to restrict withdrawals from the fund so as not to disadvantage other investors in the fund.
-4	The stated intent of this fund is to invest mainly in equity securities of emerging market companies, or those companies that derive a significant portion of their revenues or profits from emerging economies for the purpose of long-term capital growth. The plans’ trustee is required to notify the fund manager 15 days prior to a withdrawal from the fund as of the last day of any month. The fund reserves the right to suspend and compel withdrawals. The fund also reserves the right to make all or a portion of redemptions in-kind rather than in cash or in a combination of cash and in-kind.
-5	The stated intent of this fund is to invest in a diversified portfolio of international equity securities for the purpose of capital appreciation. The fund invests primarily in common stocks in the consumer goods, financial, health care, materials, energy, and information technology sectors. The plans’ trustee is required to notify the fund manager 10 days prior to a withdrawal from the fund. The fund manager retains the right to restrict withdrawals from the fund so as not to disadvantage other investors in the fund.
-6	The stated intent of this fund is to invest in U.S. Corporate bonds and U.S. Treasury securities. The fund is managed to closely match the characteristics of a long-term corporate bond index fund and seeks to maintain an average credit quality target of A- or above and a maximum 10 percent allocation to BBB rated securities. The fund’s target duration is approximately 20 years. The trustee of the fund reserves the right to delay the processing of deposits or withdrawals in order to ensure that securities transactions will be carried out in an orderly manner.
-7	The weighted-average credit quality rating of the pension assets fixed income security portfolio is investment grade with a weighted-average duration of approximately 6 years for 2014 and 2013.
-8	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 5 years for 2014 and 2013.
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				Other
		Benefits				Postretirement
						Benefits
		(Millions)
	2015	$	100			$	14
	2016	107				15
	2017	107				15
	2018	110				16
	2019	117				13
	2020-2024	609				70

Inventories_Tables

Inventories (Tables)	12 Months Ended
	Dec. 31, 2014
Inventory, Net [Abstract]
Inventories [Table Text Block]
		December 31,
		2014		2013
		(Millions)
	Natural gas liquids, olefins, and natural gas in underground storage	$	150	$	111
	Materials, supplies, and other	81		83
		$	231	$	194

Property_Plant_and_Equipment_T

Property, Plant, and Equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Property, Plant, and Equipment [Table Text Block]
		Estimated		Depreciation	December 31,
		Useful Life  (1)		Rates (1)
		(Years)		(%)	2014			2013
					(Millions)
	Nonregulated:
	Natural gas gathering and processing facilities	May-40			$	18,749		$	9,185
	Construction in progress	Not applicable			2,648			3,123
	Other	3 - 45			1,850			1,316
	Regulated:
	Natural gas transmission facilities			1.20 - 6.97	10,867			10,633
	Construction in progress			Not applicable	985			273
	Other			1.35 - 33.33	1,336			1,293
	Total property, plant, and equipment, at cost				36,435			25,823
	Accumulated depreciation and amortization				(8,354		)	(7,613		)
	Property, plant, and equipment — net				$	28,081		$	18,210
	__________
	-1	Estimated useful life and depreciation rates are presented as of December 31, 2014. Depreciation rates for regulated assets are prescribed by the FERC.
Asset Retirement Obligation [Table Text Block]
		December 31,
		2014			2013
		(Millions)
	Beginning balance	$	561		$	579
	Liabilities incurred	101			8
	Liabilities settled (1)	(21		)	(31		)
	Accretion expense	44			53
	Revisions (2)	146			(48		)
	Ending balance	$	831		$	561
	______________
	-1	For 2014 and 2013 liabilities settled include $7 million and $25 million, respectively, 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 life of the assets. 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 2013 revision primarily reflects increases in the estimated remaining useful life of the assets. The 2013 revision also includes an increase of $9 million related to changes in the timing and method of abandonment on certain of Transco’s natural gas storage caverns that were associated with a leak in 2010.

Goodwill_and_Other_Intangible_1

Goodwill and Other Intangible assets Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2014
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		Access Midstream			Total
		(Millions)
	December 31, 2013	$	646	$	—		$	646
	Acquisition	—		474			474
	December 31, 2014	$	646	$	474		$	1,120
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:
		2014					2013
		Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
		(Millions)
	Contractual customer relationships	$	10,763	$	(310	)	$	1,749	$	(105	)

Accrued_Liabilities_Tables

Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Accrued Liabilities, Current [Abstract]
Accrued Liabilities [Table Text Block]
		December 31,
		2014		2013
		(Millions)
	Interest on debt	$	268	$	167
	Employee costs	167		127
	Deferred income	82		47
	Estimated rate refund liability	1		98
	Asset retirement obligations	40		64
	Other, including other loss contingencies	342		294
		$	900	$	797

Debt_Banking_Arrangements_and_1

Debt, Banking Arrangements, and Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table Text Block]	Long-Term Debt
		December 31,
		2014			2013
		(Millions)
	Unsecured:
	Transco:
	6.4% Notes due 2016	$	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
	Pre-merger WPZ:
	3.8% Notes due 2015 (3)	750			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
	3.35% Notes due 2022	750			750
	4.5% Notes due 2023	600			600
	4.3% Notes due 2024	1,000			—
	3.9% Notes due 2025	750			—
	6.3% Notes due 2040	1,250			1,250
	5.8% Notes due 2043	400			400
	5.4% Notes due 2044	500			—
	4.9% Notes due 2045	500			—
	ACMP (1):
	5.875% Notes due 2021	750			—
	6.125% Notes due 2022	750			—
	4.875% Notes due 2023	1,400			—
	4.875% Notes due 2024	750			—
	Credit facility loans	640			—
	The Williams Companies, Inc. (WMB):
	7.875% Notes due 2021	371			371
	3.7% Notes due 2023	850			850
	4.55% Notes due 2024	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			—
	Various — 5.5% to 10.25% Notes and Debentures due 2019 to 2033	55			55
	Credit facility loans	370			—
	Capital lease obligations	5			1
	Net unamortized debt premium (discount) (2)	187			(37		)
	Total long-term debt, including current portion	20,892			11,354
	Long-term debt due within one year	(4		)	(1		)
	Long-term debt	$	20,888		$	11,353
	________________
	(1) See Note 2 – Acquisitions.
	(2) Includes premium related to the fair value of ACMP debt. See Note 2 – Acquisitions.
	(3) Presented as long-term debt due to the merged partnership’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) and capital lease obligations, for each of the next five years:
		December 31, 2014
		(Millions)
	2015	$	—
	2016	375
	2017	785
	2018	1,510
	2019	32
Schedule of Line of Credit Facilities [Table Text Block]	Credit Facilities
		December 31, 2014
		Available			Outstanding
		(Millions)
	Pre-merger WPZ credit facility (1)(3)
	Loans	$	2,500		$	—
	Letters of credit sub-limit	1,300			—
	Letters of credit under certain bilateral bank agreements				1
	ACMP credit facility (2)
	Loans	1,750			640
	Letters of credit sub-limit	200			2
	Swing line advances sub-limit	100			—
	WMB credit facility (1)
	Loans	1,500			370
	Letters of credit sub-limit	700			—
	Letters of credit under certain bilateral bank agreements				15
	________________
	(1) Under certain conditions, the amount available may be increased up to an additional $500 million.
	(2) Under certain conditions, the amount available may be increased up to an additional $250 million.
	(3) 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.
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, 2014
		(Millions)
	2015	$	83
	2016	71
	2017	55
	2018	41
	2019	33
	Thereafter	129
	Total	$	412

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2014
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				Foreign			Pension and			Total
		Flow				Currency			Other Post
		Hedges				Translation			Retirement
									Benefits
		(Millions)
	Balance at December 31, 2013	$	(1	)		$	128		$	(291	)	$	(164	)
	Other comprehensive income (loss) before reclassifications	—				(77		)	(101		)	(178		)
	Amounts reclassified from accumulated other comprehensive income (loss)	—				—			21			21
	Other comprehensive income (loss)	—				(77		)	(80		)	(157		)
	Changes in ownership of consolidated subsidiaries, net	—				(20		)	—			(20		)
	Balance at December 31, 2014	$	(1	)		$	31		$	(371	)	$	(341	)
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, 2014:
	Component		Reclassifications				Classification
			(Millions)
	Pension and other postretirement benefits:
	Amortization of prior service cost (credit) included in net periodic benefit cost		$	(8	)		Note 9 – Employee Benefit Plans
	Amortization of actuarial (gain) loss included in net periodic benefit cost		41				Note 9 – Employee Benefit Plans
	Total pension and other postretirement benefits, before income taxes		33
	Income tax benefit		(12		)		Provision (benefit) for income taxes
	Reclassifications during the period		$	21

EquityBased_Compensation_Table

Equity-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2014
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, 2014:
	Stock Options	Options			Weighted-				Aggregate
					Average				Intrinsic
					Exercise				Value
					Price
		(Millions)							(Millions)
	Outstanding at December 31, 2013	6.7			$	21.82
	Granted	0.8			$	41.76
	Exercised	(1.7	)		$	17.93
	Outstanding at December 31, 2014	5.8			$	25.86			$	110
	Exercisable at December 31, 2014	4			$	21.25			$	96
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,
		2014				2013				2012
		(Millions)
	Total intrinsic value of options exercised	$	48			$	23			$	69
	Tax benefits realized on options exercised	$	18			$	9			$	25
	Cash received from the exercise of options	$	31			$	13			$	50
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:
		2014				2013				2012
	Weighted-average grant date fair value of options for our common stock granted during the year, per share	$	7.5			$	5.94			$	5.65
	Weighted-average assumptions:
	Dividend yield	4.2		%		4.3		%		3.7		%
	Volatility	28		%		29.7		%		30		%
	Risk-free interest rate	2.2		%		1.4		%		1.3		%
	Expected life (years)	6.5				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, 2014.
	Restricted Stock Units Outstanding	Shares			Weighted-
					Average
					Fair Value (1)
		(Millions)
	Nonvested at December 31, 2013	3.5			$	27.16
	Granted	1.4			$	42.79
	Forfeited	(0.1	)		$	29.57
	Vested	(1.2	)		$	24.07
	Nonvested at December 31, 2014	3.6			$	33.9
	______________
	-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 or the grant-date market price less dividends projected to be paid over the vesting period. Restricted stock units generally vest after three years.
Other restricted stock unit information [Table Text Block]
	Value of Restricted Stock Units	2014				2013				2012
	Weighted-average grant date fair value of restricted stock units granted during the year, per share	$	42.79			$	30.43			$	20.61
	Total fair value of restricted stock units vested during the year ($’s in millions)	$	27			$	27			$	22
Access Midstream 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 ACMP restricted stock unit activity and related information for the six months ended December 31, 2014:
	Restricted Stock Units Outstanding	Units			Weighted-
					Average
					Fair Value
		(Millions)
	Granted	1.3			$	59.67
	Forfeited	—			$	63.89
	Vested	—			$	63.75
	Nonvested at December 31, 2014	1.3			$	59.35

Fair_Value_Measurements_Guaran1

Fair Value Measurements Guarantees and Concentration of Credit Risk (Tables)	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Assets and Liabilities Measured On Recurring Basis [Table Text Block]
								Fair Value Measurements Using
		Carrying			Fair			Quoted		Significant			Significant
		Amount			Value			Prices In		Other			Unobservable
								Active		Observable			Inputs
								Markets for		Inputs			(Level 3)
								Identical		(Level 2)
								Assets
								(Level 1)
		(Millions)
	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)	(20,887		)	(21,131		)	—		(21,131		)	—
	Guarantee	(31		)	(27		)	—		(27		)	—
	Assets (liabilities) at December 31, 2013:
	Measured on a recurring basis:
	ARO Trust investments	$	33		$	33		$	33	$	—		$	—
	Energy derivatives assets not designated as hedging instruments	3			3			—		—			3
	Energy derivatives liabilities not designated as hedging instruments	(3		)	(3		)	—		(1		)	(2		)
	Additional disclosures:
	Notes receivable and other	77			140			1		6			133
	Long-term debt, including current portion (1)	(11,353		)	(11,971		)	—		(11,971		)	—
	Guarantee	(32		)	(29		)	—		(29		)	—
	________________
	(1) Excludes capital 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,
		2014			2013
		(Millions)
	NGLs, natural gas, and related products and services	$	730		$	341
	Transportation of natural gas and related products	175			193
	Income tax receivable	167			74
	Other	67			66
	Total	$	1,139		$	674

Segment_Disclosures_Tables

Segment Disclosures (Tables)	12 Months Ended
	Dec. 31, 2014
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:
		2014	$	7,229		$	408		$	7,637
		2013		6,703			157			6,860
		2012		7,335			151			7,486
	Long-lived assets:
		2014	$	38,290		$	1,364		$	39,654
		2013		19,260			1,240			20,500
		2012		16,940			880			17,820
Reconciliation of segment revenues and segment profit (loss) [Table Text Block]	The following table reflects the reconciliation of Segment revenues and Segment profit (loss) to Total revenues and Operating income (loss) as reported in the Consolidated Statement of Income and Other financial information related to Long-lived assets.
		Williams				Access				Williams			Other			Eliminations			Total
		Partners				Midstream				NGL & Petchem
										Services
		(Millions)
	2014
	Segment revenues:
	Service revenues
	External	$	3,106			$	781			$	—		$	229		$	—		$	4,116
	Internal	1				—				—			30			(31		)	—
	Total service revenues	3,107				781				—			259			(31		)	4,116
	Product sales
	External	3,521				—				—			—			—			3,521
	Internal	—				—				—			—			—			—
	Total product sales	3,521				—				—			—			—			3,521
	Total revenues	$	6,628			$	781			$	—		$	259		$	(31	)	$	7,637
	Segment profit (loss)	$	1,743			$	2,803			$	(115	)	$	4					$	4,435
	Less:
	Equity earnings (losses)	132				90				(78		)	—						144
	Gain on remeasurement of equity-method investment	—				2,544				—			—						2,544
	Income (loss) from investments	—				1				(1		)	—						—
	Segment operating income (loss)	$	1,611			$	168			$	(36	)	$	4					1,747
	General corporate expenses																		(178		)
	Operating income (loss)																		$	1,569
	Other financial information:
	Additions to long-lived assets (1)	$	3,449			$	16,964			$	291		$	54		$	(2	)	$	20,756
	Depreciation and amortization	855				296				—			25						1,176
	__________________
	(1) 2014 Additions to long-lived assets within our Access Midstream segment primarily includes the acquisition-date fair value of long-lived assets from the ACMP Acquisition (see Note 2 - Acquisitions).
	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
	Segment profit (loss)	$	1,677			$	61			$	(32	)	$	(5	)				$	1,701
	Less:
	Equity earnings (losses)	104				30				—			—						134
	Income (loss) from investments	(3		)		31				—			—						28
	Segment operating income (loss)	$	1,576			$	—			$	(32	)	$	(5	)				1,539
	General corporate expenses																		(164		)
	Operating income (loss)																		$	1,375
	Other financial information:
	Additions to long-lived assets	$	3,409			$	—			$	295		$	27					$	3,731
	Depreciation and amortization	791				—				—			24						815
		Williams				Access				Williams			Other			Eliminations			Total
		Partners				Midstream				NGL & Petchem
										Services
		(Millions)
	2012
	Segment revenues:
	Service revenues
	External	$	2,714			$	—			$	—		$	15		$	—		$	2,729
	Internal	—				—				—			12			(12		)	—
	Total service revenues	2,714				—				—			27			(12		)	2,729
	Product sales
	External	4,757				—				—			—			—			4,757
	Internal	—				—				—			—			—			—
	Total product sales	4,757				—				—			—			—			4,757
Total revenues	$	7,471			$	—			$	—		$	27		$	(12	)	$	7,486
Segment profit (loss)	$	1,907			$	—			$	(3	)	$	56					$	1,960
Less:
Equity earnings (losses)	111				—				—			—						111
Income (loss) from investments	(4		)		—				—			53						49
Segment operating income (loss)	$	1,800			$	—			$	(3	)	$	3					1,800
General corporate expenses																		(188		)
Operating income (loss)																		$	1,612
Other financial information:
Additions to long-lived assets	$	5,851			$	—			$	136		$	31					$	6,018
Depreciation and amortization	734				—				—			22						756
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
			31-Dec-14				31-Dec-13				31-Dec-14			31-Dec-13
			(Millions)
	Williams Partners		$	26,298			$	23,571			$	2,395		$	2,187
	Access Midstream		23,024				2,161				6,004			2,161
	Williams NGL & Petchem Services		612				486				—			12
	Other		1,220				1,359				1			—
	Eliminations		(591		)		(435		)		—			—
	Total		$	50,563			$	27,142			$	8,400		$	4,360

Schedule_I_Condensed_Financial1

Schedule I Condensed Financial Information of Parent Company Only (Tables)	12 Months Ended
	Dec. 31, 2014
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,
		2014			2013			2012
		(Millions, except per-share amounts)
	Equity in earnings of consolidated subsidiaries	$	1,799		$	1,564		$	1,895
	Equity earnings (losses) from investment in Access Midstream Partners	(7		)	30			—
	Interest incurred — external	(206		)	(156		)	(128		)
	Interest incurred — affiliate	(797		)	(722		)	(816		)
	Interest income — affiliate	10			71			84
	Gain on remeasurement of equity-method investment	2,544			—			—
	Other income (expense) — net	(13		)	32			3
	Income from continuing operations before income taxes	3,330			819			1,038
	Provision for income taxes	1,220			378			315
	Income (loss) from continuing operations	2,110			441			723
	Income (loss) from discontinued operations	4			(11		)	136
	Net income (loss)	$	2,114		$	430		$	859
	Basic earnings (loss) per common share:
	Income (loss) from continuing operations	$	2.93		$	0.65		$	1.17
	Income (loss) from discontinued operations	0.01			(.02		)	0.22
	Net income (loss)	$	2.94		$	0.63		$	1.39
	Weighted-average shares (thousands)	719,325			682,948			619,792
	Diluted earnings (loss) per common share:
	Income (loss) from continuing operations	2.91			0.64			$	1.15
	Income (loss) from discontinued operations	0.01			(.02		)	0.22
	Net income (loss)	$	2.92		$	0.62		$	1.37
	Weighted-average shares (thousands)	723,641			687,185			625,486
	Other comprehensive income (loss):
	Equity in other comprehensive income (loss) of consolidated subsidiaries	$	(96	)	$	(41	)	$	21
	Other comprehensive income (loss) attributable to The Williams Companies, Inc.	(80		)	239			6
	Other comprehensive income (loss)	(176		)	198			27
	Less: Other comprehensive income (loss) attributable to noncontrolling interests	(19		)	—			—
	Comprehensive income (loss) attributable to The Williams Companies, Inc.	$	1,957		$	628		$	886
	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,
		2014			2013
		(Millions)
	ASSETS
	Current assets:
	Cash and cash equivalents	$	49		$	282
	Other current assets and deferred charges	246			167
	Total current assets	295			449
	Investments in and advances to consolidated subsidiaries	31,405			19,162
	Investment in Access Midstream Partners	—			2,161
	Property, plant, and, equipment — net	99			68
	Other noncurrent assets	46			34
	Total assets	$	31,845		$	21,874
	LIABILITIES AND STOCKHOLDERS’ EQUITY
	Current liabilities:
	Accounts payable	$	27		$	26
	Long-term debt due within one year	—			1
	Other current liabilities	174			147
	Total current liabilities	201			174
	Long-term debt	4,562			2,296
	Notes payable — affiliates	13,295			10,830
	Pension, other postretirement, and other noncurrent liabilities	409			282
	Deferred income taxes	4,601			3,428
	Contingent liabilities and commitments
	Equity:
	Common stock	782			718
	Other stockholders’ equity	7,995			4,146
	Total stockholders’ equity	8,777			4,864
	Total liabilities and stockholders’ equity	$	31,845		$	21,874
	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,
		2014			2013			2012
		(Millions)
	NET CASH FLOWS PROVIDED (USED) BY OPERATING ACTIVITIES	$	(500	)	$	19		$	(11	)
	FINANCING ACTIVITIES:
	Proceeds from long-term debt	2,935			—			848
	Payments of long-term debt	(671		)	(1		)	(28		)
	Changes in notes payable to affiliates	2,465			1,892			520
	Tax benefit of stock-based awards	25			19			44
	Proceeds from issuance of common stock	3,416			18			2,550
	Dividends paid	(1,412		)	(982		)	(742		)
	Other — net	(17		)	(3		)	(7		)
	Net cash provided (used) by financing activities	6,741			943			3,185
	INVESTING ACTIVITIES:
	Capital expenditures	(54		)	(23		)	(18		)
	Purchase of Access Midstream Partners	(5,995		)	—			—
	Purchase of investment in Access Midstream Partners	—			(4		)	(2,179		)
	Changes in investments in and advances to consolidated subsidiaries	(450		)	(985		)	(953		)
	Other — net	25			(8		)	24
	Net cash provided (used) by investing activities	(6,474		)	(1,020		)	(3,126		)
	Increase (decrease) in cash and cash equivalents	(233		)	(58		)	48
	Cash and cash equivalents at beginning of year	282			340			292
	Cash and cash equivalents at end of year	$	49		$	282		$	340
	See accompanying notes.

Description_of_Business_and_Ba

Description of Business and Basis of Presentation (Details) (USD $)	12 Months Ended			6 Months Ended	1 Months Ended		3 Months Ended	0 Months Ended	3 Months Ended	6 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 20, 2012	Jul. 02, 2014	Oct. 31, 2014	Feb. 28, 2014	Jun. 30, 2014	Feb. 02, 2015	Sep. 30, 2014	Dec. 31, 2014	Jul. 01, 2014
Basis Of Presentation [Abstract]
Master limited partnership, general partner ownership percentage			2.00%
Changes in ownership of consolidated subsidiaries, net	$44,000,000	($243,000,000)
Common Management Transaction [Member]
Basis Of Presentation [Abstract]
Revenue from Related Parties	115,000,000	131,000,000
Access Midstream Partners Acquisition [Member]
Description Of Business [Abstract]
Payments to Acquire Businesses, Gross				5,995,000,000
Basis Of Presentation [Abstract]
Master limited partnership, general partner ownership percentage				2.00%
Canada Acquisition [Member]
Description Of Business [Abstract]
Number Of Limited Partner Units Received1						25,577,521
Basis Of Presentation [Abstract]
Proceeds from Divestiture of Businesses						56,000,000	31,000,000
Number Of Limited Partner Units Received1						25,577,521
Payments for Previous Acquisition					56,000,000
Reduction in incentive distribution rights payment					2,000,000
Limited Partner [Member] | Access Midstream Partners Acquisition [Member]
Description Of Business [Abstract]
Number Of Limited Partner Units Received1				55,100,000
Basis Of Presentation [Abstract]
Number Of Limited Partner Units Received1				55,100,000
General Partner [Member]
Basis Of Presentation [Abstract]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage	100.00%									100.00%
General Partner [Member] | Access Midstream Partners Acquisition [Member]
Description Of Business [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired											50.00%
Capital in excess of par value [Member]
Basis Of Presentation [Abstract]
Changes in ownership of consolidated subsidiaries, net	-73,000,000	409,000,000
Noncontrolling Interest [Member]
Basis Of Presentation [Abstract]
Changes in ownership of consolidated subsidiaries, net	137,000,000	-652,000,000
Deferred Income Taxes [Member]
Basis Of Presentation [Abstract]
Income Tax Effects Allocated Directly to Equity, Other	44,000,000
Accumulated Other Comprehensive Income (Loss) [Member]
Basis Of Presentation [Abstract]
Changes in ownership of consolidated subsidiaries, net	-20,000,000	0
Gulfstream Natural Gas System, L.L.C.[Member]
Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage	50.00%									50.00%
Utica East Ohio Midstream, LLC [Member]
Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage	49.00%									49.00%
Delaware Basin Gas Gathering System [Member]
Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage	50.00%									50.00%
Appalachia Midstream Services, LLC [Member]
Description Of Business [Abstract]
Number Of Gathering Systems	11
Williams Partners L.P. [Member]
Basis Of Presentation [Abstract]
Master limited partnership, general partner ownership percentage						2.00%
Williams Partners L.P. [Member] | Merger [Member] | Publicly Held WPZ Common Units into ACMP Common Units [Member] | Subsequent Event [Member]
Description Of Business [Abstract]
Conversion Ratio								0.86672
Williams Partners L.P. [Member] | Merger [Member] | Privately Held WPZ Units Into ACMP Common Units [Member] | Subsequent Event [Member]
Description Of Business [Abstract]
Conversion Ratio								0.80036
Williams Partners L.P. [Member] | Merger [Member] | ACMP Units Into Merged Partnership Units [Member] | Subsequent Event [Member]
Description Of Business [Abstract]
Conversion Ratio								1.06152
Williams Partners L.P. [Member] | Merger [Member] | Class D WPZ Units Into WPZ Common Units [Member] | Subsequent Event [Member]
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									1,080,448
Williams Partners L.P. [Member] | General and Limited Partner [Member]
Description Of Business [Abstract]
Master limited partnership ownership percentage	66.00%
Williams Partners L.P. [Member] | General and Limited Partner [Member] | Merger [Member] | Subsequent Event [Member]
Description Of Business [Abstract]
Master limited partnership ownership percentage								60.00%
Access Midstream Partners Lp [Member] | Access Midstream Partners Acquisition [Member]
Basis Of Presentation [Abstract]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage											26.00%
Access Midstream Partners Lp [Member] | General and Limited Partner [Member]
Description Of Business [Abstract]
Master limited partnership ownership percentage										51.00%
Access Midstream Partners Lp [Member] | Limited Partner [Member]
Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage			24.00%
Basis Of Presentation [Abstract]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage	50.00%									50.00%
Williams Partners [Member]
Description Of Business [Abstract]
Number Of Interstate Natural Gas Pipelines	2
Williams Partners [Member] | Gulfstream Natural Gas System, L.L.C.[Member]
Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage	50.00%									50.00%
Williams Partners [Member] | Constitution Pipeline Company LLC [Member]
Description Of Business [Abstract]
Variable Interest Entity Ownership Percentage	41.00%
Access Midstream [Member] | Utica East Ohio Midstream, LLC [Member]
Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage	49.00%									49.00%
Access Midstream [Member] | Delaware Basin Gas Gathering System [Member]
Description Of Business [Abstract]
Equity Method Investment, Ownership Percentage	50.00%									50.00%
Access Midstream [Member] | Appalachia Midstream Services, LLC [Member]
Description Of Business [Abstract]
Subsidiary of Limited Liability Company or Limited Partnership, Ownership Interest	45.00%
Number Of Gathering Systems	$11

Summary_of_Significant_Account

Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Regulatory Assets and Liabilities Disclosure [Abstract]
Regulatory Assets, Current	$81	$39
Regulatory Assets, Noncurrent	337	353
Total regulatory assets	418	392
Regulatory Liability, Current	11	19
Regulatory Liability, Noncurrent	375	329
Total regulatory liabilities	386	348
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) (USD $)	12 Months Ended							6 Months Ended	2 Months Ended	4 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 20, 2012	Dec. 31, 2012		Jul. 02, 2014	Feb. 17, 2012	Apr. 27, 2012	Jul. 01, 2014
Equity Method Investments and Joint Ventures [Abstract]
Payments to Acquire Equity Method Investments	$482,000,000		$455,000,000			$2,651,000,000
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	2,544,000,000	[1]	0	[1]		0	[1]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill	1,120,000,000		646,000,000
Williams Partners [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill	646,000,000		646,000,000
Access Midstream [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Goodwill	474,000,000		0
Access Midstream [Member]
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investment, Ownership Percentage			24.00%
Payments to Acquire Equity Method Investments					2,190,000,000
Business Combination, Consideration Transferred [Abstract]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value								4,600,000,000
Laser Acquisition [Member]
Business Combination, Consideration Transferred [Abstract]
Payments to Acquire Businesses, Gross									325,000,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares									7,531,381
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable									441,000,000
Laser Acquisition [Member] | Williams Partners [Member]
Business Combination, Consideration Transferred [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired									100.00%
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Assets held-for-sale									18,000,000
Other current assets									3,000,000
Property, plant and equipment									158,000,000
Goodwill									290,000,000
Intangible assets									318,000,000
Current liabilities									-21,000,000
Other noncurrent liabilities									0
Identifiable net assets acquired									476,000,000
Total									766,000,000
Caiman Acquisition [Member]
Business Combination, Consideration Transferred [Abstract]
Payments to Acquire Businesses, Gross										1,720,000,000
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares										11,779,296
Business Combination, Consideration Transferred, Equity Interests Issued and Issuable										603,000,000
Caiman Acquisition [Member] | Williams Partners [Member]
Business Combination, Consideration Transferred [Abstract]
Business Acquisition, Percentage of Voting Interests Acquired										100.00%
Business Combination, Acquisition Related Costs						16,000,000
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Assets held-for-sale										0
Other current assets										16,000,000
Property, plant and equipment										656,000,000
Goodwill										356,000,000
Intangible assets										1,393,000,000
Current liabilities										-94,000,000
Other noncurrent liabilities										-3,000,000
Identifiable net assets acquired										1,968,000,000
Total										2,324,000,000
Access Midstream Partners Acquisition [Member]
Business Combination, Consideration Transferred [Abstract]
Payments to Acquire Businesses, Gross								5,995,000,000
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	2,500,000,000
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 Net Income (Loss)	622,000,000		356,000,000
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	781,000,000
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual	165,000,000
Business Acquisition, Pro Forma Revenue	8,181,000,000		7,906,000,000
Access Midstream Partners Acquisition [Member] | Selling, General and Administrative Expenses [Member]
Business Combination, Consideration Transferred [Abstract]
Business Combination, Acquisition Related Costs	16,000,000
Access Midstream Partners Acquisition [Member] | Interest Expense [Member]
Business Combination, Consideration Transferred [Abstract]
Business Combination, Acquisition Related Costs	9,000,000
Access Midstream Partners Acquisition [Member] | Income Loss From Equity Method Investment [Member]
Business Combination, Consideration Transferred [Abstract]
Business Combination, Integration Related Costs	19,000,000
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] | Access Midstream [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Accounts receivable											168,000,000
Other current assets											63,000,000
Investments											5,872,000,000
Property, plant and equipment											7,015,000,000
Goodwill											474,000,000
Intangible assets											9,009,000,000
Current liabilities											-408,000,000
Debt											-4,052,000,000
Other noncurrent liabilities											-9,000,000
Business Combination, Goodwill [Abstract]
Business Acquisition, Goodwill, Expected Tax Deductible Amount											474,000,000
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] | Access Midstream [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Noncontrolling interest											-6,544,000,000
Access Midstream Partners Acquisition [Member] | ACMP's subsidiaries [Member] | Access Midstream [Member]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net [Abstract]
Noncontrolling interest											-958,000,000
General Partner [Member]
Business Combination, Consideration Transferred [Abstract]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage	100.00%
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%
Business Combination, Consideration Transferred [Abstract]
Business Combination, Step Acquisition, Equity Interest in Acquiree, Including Subsequent Acquisition, Percentage	50.00%
[1]	Items also included in Segment profit (loss). (See Note 19 b Segment Disclosures.)

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (USD $)	12 Months Ended						3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Mar. 31, 2014
Variable Interest Entity [Line Items]
Income (Loss) from Equity Method Investments	($144)	[1]	($134)	[1]	($111)	[1]
Laurel Mountain [Member]
Variable Interest Entity [Line Items]
Equity Method Investment, Ownership Percentage	69.00%
Caiman Energy II LLC [Member]
Variable Interest Entity [Line Items]
Equity Method Investment, Ownership Percentage	58.00%
Variable Interest Entity, Primary Beneficiary [Member] | Cash and cash equivalents [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	113		130	[2]
Variable Interest Entity, Primary Beneficiary [Member] | Accounts receivable [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	52		0	[2]
Variable Interest Entity, Primary Beneficiary [Member] | Other current assets [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	3		0	[2]
Variable Interest Entity, Primary Beneficiary [Member] | Property, plant, and equipment, net [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	2,794		1,113	[2]
Variable Interest Entity, Primary Beneficiary [Member] | Goodwill [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	103		0	[2]
Variable Interest Entity, Primary Beneficiary [Member] | Intangible assets, net [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	1,493		0	[2]
Variable Interest Entity, Primary Beneficiary [Member] | Other noncurrent assets [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	14		0
Variable Interest Entity, Primary Beneficiary [Member] | Accounts payable [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	-48		-146	[2]
Variable Interest Entity, Primary Beneficiary [Member] | Accrued liabilities [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	-36		-3	[2]
Variable Interest Entity, Primary Beneficiary [Member] | Current deferred revenue [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	-45		-10	[2]
Variable Interest Entity, Primary Beneficiary [Member] | Asset retirement obligation [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	-94		0	[2]
Variable Interest Entity, Primary Beneficiary [Member] | Noncurrent deferred income taxes [Member]
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	-13		0	[2]
Variable Interest Entity, Primary Beneficiary [Member] | 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	-395		-115	[2]
Variable Interest Entity, Primary Beneficiary [Member] | Gulfstar One [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	51.00%
Variable Interest Entity, Primary Beneficiary [Member] | Gulfstar One [Member] | Estimated Remaining Construction Costs For Variable Interest Entity [Member]
Variable Interest Entity [Line Items]
Estimated remaining construction costs	150
Variable Interest Entity, Primary Beneficiary [Member] | Constitution Pipeline Company Llc [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	41.00%
Variable Interest Entity, Primary Beneficiary [Member] | Constitution Pipeline Company Llc [Member] | Estimated Remaining Construction Costs For Variable Interest Entity [Member]
Variable Interest Entity [Line Items]
Estimated remaining construction costs	628
Variable Interest Entity, Primary Beneficiary [Member] | Cardinal Gas Services LLC [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	66.00%
Variable Interest Entity, Primary Beneficiary [Member] | Jackalope Gas Gathering Services LLC [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	50.00%
Variable Interest Entity, Not Primary Beneficiary [Member] | Bluegrass Pipeline Company Llc [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	50.00%
Deconsolidation, Gain (Loss), Amount							0
Income (Loss) from Equity Method Investments							67
Variable Interest Entity, Not Primary Beneficiary [Member] | Moss Lake [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity Ownership Percentage	50.00%
Income (Loss) from Equity Method Investments							$4
[1]	Items also included in Segment profit (loss). (See Note 19 b Segment Disclosures.)
[2]	Amounts presented for December 31, 2013, include balances related to Bluegrass Pipeline. See discussion of the subsequent deconsolidation of Bluegrass Pipeline below.

Discontinued_Operations_Detail

Discontinued Operations (Details) (USD $)	12 Months Ended	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Former Alaska Refinery [Member]
Summarized Results of Discontinued Operations
Income (loss) from discontinued operations before income taxes	$15
Former Venezuela Operations [Member]
Summarized Results of Discontinued Operations
Income (loss) from discontinued operations before income taxes			144
Textuals [Abstract]
Cash Payments Received Related To Former Venezuela Operations Settlement		98
Cash Installments Related To Former Operations Settlement		15
Assets, Fair Value Disclosure [Abstract]
Notes Receivable, Fair Value Disclosure		$88
Fair Value Inputs [Abstract]
Fair Value Inputs, Discount Rate		12.00%
Former Venezuela Operations [Member] | Minimum [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Probability of Default		15.00%
Former Venezuela Operations [Member] | Maximum [Member]
Fair Value Inputs [Abstract]
Fair Value Inputs, Probability of Default		100.00%

Investing_Activities_Details

Investing Activities (Details) (USD $)	12 Months Ended						6 Months Ended	12 Months Ended	6 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Jun. 30, 2014	Dec. 20, 2012	Dec. 31, 2014		Mar. 31, 2013	Dec. 31, 2010
Investing income
Gain on remeasurement of equity-method investment	$2,544,000,000	[1]	$0	[1]	$0	[1]
Equity earnings (losses)	144,000,000	[1]	134,000,000	[1]	111,000,000	[1]
Income (loss) from investments	0	[1]	28,000,000	[1]	49,000,000	[1]
Interest income and other	43,000,000		53,000,000		28,000,000
Total investing income	2,731,000,000		215,000,000		188,000,000
Investments
Equity Method Investments	8,400,000,000		4,360,000,000						8,400,000,000
Dividends and distributions
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	3,700,000,000								3,700,000,000
Equity Method Investment, payments to purchase or contributions	482,000,000		455,000,000		2,651,000,000
Equity method investment, dividends or distributions	409,000,000		247,000,000		173,000,000
Related Party Transactions [Abstract]
Related Party Transaction, Purchases from Related Party	197,000,000		161,000,000		186,000,000
Related party transactions, payable	13,000,000		13,000,000						13,000,000
Related Party Transaction, Expenses from Transactions with Related Party	75,000,000		67,000,000		75,000,000
Summarized Financial Position of Equity Method Investments
Current assets	599,000,000		689,000,000						599,000,000
Noncurrent assets	9,135,000,000		13,621,000,000						9,135,000,000
Current liabilities	-850,000,000		-573,000,000						-850,000,000
Noncurrent liabilities	-954,000,000		-4,563,000,000						-954,000,000
Noncontrolling interests	0		-254,000,000						0
Summarized Results of Operations of Equity Method Investments
Gross revenue	1,623,000,000		2,406,000,000		1,821,000,000
Operating income	534,000,000		699,000,000		557,000,000
Net income	460,000,000		627,000,000		488,000,000
Appalachia Midstream Services, LLC [Member]
Investments
Equity Method Investments	3,033,000,000	[2]	0	[2]					3,033,000,000	[2]
Number Of Gathering Systems	11
Dividends and distributions
Equity Method Investment, payments to purchase or contributions	84,000,000		0		0
Equity method investment, dividends or distributions	120,000,000		0		0
Appalachia Midstream Services, LLC [Member] | Minimum [Member]
Investments
Equity Method Investment, Ownership Percentage	33.75%								33.75%
Appalachia Midstream Services, LLC [Member] | Maximum [Member]
Investments
Equity Method Investment, Ownership Percentage	67.50%								67.50%
Appalachia Midstream Services, LLC [Member] | Average [Member]
Investments
Equity Method Investment, Ownership Percentage	45.00%								45.00%
Appalachia Midstream Services, LLC [Member] | Application Of The Equity-Method Of Accounting [Member] | Minimum [Member]
Investments
Equity Method Investment, Ownership Percentage	50.00%								50.00%
Delaware Basin Gas Gathering System [Member]
Investments
Equity Method Investments	1,478,000,000	[2]	0	[2]					1,478,000,000	[2]
Equity Method Investment, Ownership Percentage	50.00%								50.00%
Utica East Ohio Midstream, LLC [Member]
Investments
Equity Method Investments	1,411,000,000	[2]	0	[2]					1,411,000,000	[2]
Equity Method Investment, Ownership Percentage	49.00%								49.00%
Dividends and distributions
Equity Method Investment, payments to purchase or contributions	57,000,000		0		0
Discovery Producer Services LLC [Member]
Investments
Equity Method Investments	602,000,000	[3]	527,000,000	[3]					602,000,000	[3]
Equity Method Investment, Ownership Percentage	60.00%								60.00%
Dividends and distributions
Equity Method Investment, payments to purchase or contributions	106,000,000		193,000,000		169,000,000
Equity method investment, dividends or distributions	36,000,000		12,000,000		21,000,000
Discovery Producer Services LLC [Member] | Proportionate Share Of Amounts Remaining For Capital Projects [Member]
Dividends and distributions
Expected contributions to equity method investees for expansion projects	98,000,000								98,000,000
Laurel Mountain Midstream, LLC [Member]
Investments
Equity Method Investments	459,000,000	[3]	481,000,000	[3]					459,000,000	[3]
Equity Method Investment, Ownership Percentage	69.00%								69.00%
Dividends and distributions
Equity Method Investment, payments to purchase or contributions	12,000,000		42,000,000		174,000,000
Equity method investment, dividends or distributions	39,000,000		0		0
Laurel Mountain Midstream, LLC [Member] | Proportionate Share Of Amounts Remaining For Capital Projects [Member]
Dividends and distributions
Expected contributions to equity method investees for expansion projects	92,000,000								92,000,000
Overland Pass Pipeline Company LLC [Member]
Investments
Equity Method Investments	453,000,000		452,000,000						453,000,000
Equity Method Investment, Ownership Percentage	50.00%								50.00%
Dividends and distributions
Equity method investment, dividends or distributions	27,000,000		27,000,000		28,000,000
Caiman Energy II, LLC [Member]
Investments
Equity Method Investments	432,000,000	[3]	256,000,000	[3]					432,000,000	[3]
Equity Method Investment, Ownership Percentage	58.00%								58.00%
Dividends and distributions
Equity Method Investment, payments to purchase or contributions	175,000,000		192,000,000		69,000,000
Gulfstream Natural Gas System, L.L.C.[Member]
Investments
Equity Method Investments	317,000,000		333,000,000						317,000,000
Equity Method Investment, Ownership Percentage	50.00%								50.00%
Dividends and distributions
Equity method investment, dividends or distributions	81,000,000		81,000,000		79,000,000
Access Midstream Partners [Member]
Investing income
Equity earnings (losses)			93,000,000				23,000,000
Income (loss) from investments			31,000,000
Investments
Equity Method Investments	0		2,161,000,000						0
Equity Method Investment, Ownership Percentage			24.00%
Dividends and distributions
Equity Method Investment, payments to purchase or contributions								2,190,000,000
Equity method investment, dividends or distributions	64,000,000		93,000,000		0
Access Midstream Partners [Member] | Limited Partner [Member]
Investments
Equity Method Investment, Ownership Percentage			23.00%								24.00%
Access Midstream Partners [Member] | Adjustment For Amortization Of Difference Between Carrying Amount And Underlying Equity [Member]
Investing income
Equity earnings (losses)			-63,000,000				-30,000,000
Other [Member]
Investments
Equity Method Investments	215,000,000		150,000,000						215,000,000
Bluegrass Pipeline [Member]
Investing income
Equity earnings (losses)	-67,000,000
Moss Lake [Member]
Investing income
Equity earnings (losses)	-4,000,000
Accroven SRL [Member]
Investing income
Income (loss) from investments					53,000,000
Interest income and other					10,000,000
Investments
Equity Method Investment, Ownership Percentage												50.00%
Aux Sable Liquid Products LP [Member]
Dividends and distributions
Equity method investment, dividends or distributions	15,000,000		20,000,000		28,000,000
Former Venezuela Operations [Member]
Investing income
Interest income and other	41,000,000		50,000,000		7,000,000
Access Midstream [Member]
Investing income
Equity earnings (losses)									146,000,000
Access Midstream [Member] | Adjustment For Amortization Of Difference Between Carrying Amount And Underlying Equity [Member]
Investing income
Equity earnings (losses)									($49,000,000)
[1]	Items also included in Segment profit (loss). (See Note 19 b Segment Disclosures.)
[2]	We acquired these investments in the ACMP Acquisition. (Note 2 b Acquisitions.) As discussed in Note 1 b Description of Business, Basis of Presentation, and Summary of Significant Accounting Policies, the Appalachia Midstream Investments include investments in 11 different gathering systems in the Marcellus Shale. Ownership interests range from 33.75 percent to 67.50 percent, resulting in an overall approximate average interest of 45 percent. For those investments where we own in excess of 50 percent, we apply the equity-method of accounting due to the significant participation rights of our partners such that we do not control.
[3]	We account for these investments under the equity method of accounting due to the significant participatory rights of our partners such that we do not control or are otherwise not the primary beneficiary of the investments.

Other_Income_and_Expense_Detai

Other Income and Expense (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Loss related to sale of certain assets	$56	$28	($52)
Williams Partners [Member]
Segment Reporting Information [Line Items]
Contingency gain settlement	-154	0	0
Impairment of certain assets	40	0	0
Net gain related to partial acreage dedication release	-12	0	0
Amortization of regulatory assets associated with asset retirement obligations	33	30	7
Project feasibility costs	2	4	21
Capitalization of project feasibility costs previously expensed	-5	-1	-19
Williams Partners [Member] | Producer Claim [Member]
Segment Reporting Information [Line Items]
Loss associated with a producer claim	0	25	0
Williams Partners [Member] | Asset Impairment for Regulatory Action [Member]
Segment Reporting Information [Line Items]
Impairment of certain assets	-3	12	0
Insurance recoveries associated with the Eminence abandonment	0	-16	0
Access Midstream [Member]
Segment Reporting Information [Line Items]
Loss related to sale of certain assets	10	0	0
Impairment of certain pipe and equipment held for sale	12	0	0
Williams NGL & Petchem Services [Member]
Segment Reporting Information [Line Items]
Impairment of certain assets	$0	$20	$0

Other_Income_and_Expense_Detai1

Other Income and Expense (Details Textuals) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Allowance for Funds Used During Construction, Capitalized Cost of Equity	$44	$22	$21
Restructuring charges for corporate realignment			26
Employee costs [Member] | Selling, General and Administrative Expenses [Member]
Segment Reporting Information [Line Items]
Business Combination, Integration Related Costs	15
Employee costs [Member] | Operation and maintenance [Member]
Segment Reporting Information [Line Items]
Business Combination, Integration Related Costs	15
Merger [Member]
Segment Reporting Information [Line Items]
Business Combination, Integration Related Costs	11
Other Restructuring [Member]
Segment Reporting Information [Line Items]
Business Combination, Integration Related Costs	10
Williams Partners [Member]
Segment Reporting Information [Line Items]
Gain Related To Claims From Purchase Of Business In A Prior Period	154	0	0
Project development costs	2	4	21
Williams Partners [Member] | Geismar Incident [Member]
Segment Reporting Information [Line Items]
Insurance deductible expense		13
Insurance Recoveries	246	50
Insurable Expense in Excess of our Deductibles	14	10
Williams Partners [Member] | Geismar Incident [Member] | Property Damage And Business Interruption [Member]
Segment Reporting Information [Line Items]
Maximum insurance recoverable amount	500
Williams Partners [Member] | Geismar Incident [Member] | Property Damage [Member]
Segment Reporting Information [Line Items]
Insurance deductibles	10
Williams Partners [Member] | Geismar Incident [Member] | Business Interruption [Member]
Segment Reporting Information [Line Items]
Duration of waiting period before business interrutpion coverage begins	60 days
Williams Partners [Member] | Geismar Incident [Member] | General Liability [Member]
Segment Reporting Information [Line Items]
Maximum insurance recoverable amount	610
Insurance deductibles	2
Williams Partners [Member] | Geismar Incident [Member] | Workers Compensation [Member]
Segment Reporting Information [Line Items]
Insurance deductibles	1
Williams NGL & Petchem Services [Member] | Bluegrass Pipeline Company Llc [Member]
Segment Reporting Information [Line Items]
Project development costs	$18

Provision_for_Income_Taxes_Tax

Provision for Income Taxes Tax Provison (Benefit) Table (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current :
Federal	($9)	($17)	$91
State	2	7	17
Foreign	10	-13	40
Total	3	-23	148
Deferred:
Federal	1,108	348	220
State	119	40	-13
Foreign	19	36	5
Total	1,246	424	212
Provision (benefit) for income taxes	$1,249	$401	$360

Provision_for_Income_Taxes_Rec

Provision for Income Taxes Reconciliations to Recorded Tax Provision (Benefit) Table (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Effective Income Tax Rate Reconciliation [Abstract]
Provision (benefit) at statutory rate		$1,255	$378	$451
Increases (decreases) in taxes resulting from:
Impact of nontaxable noncontrolling interests		-75	-78	-72
State income taxes (net of federal benefit)		82	26	2
Foreign operations - net		-11	-32	-36
Taxes on undistributed earnings of foreign subsidiaries - net	99	-37	99	0
Other - net		35	8	15
Provision (benefit) for income taxes		$1,249	$401	$360

Provision_for_Income_Taxes_Def

Provision for Income Taxes Deferred Tax Table (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Deferred tax liabilities:
Property, plant, and equipment	$4	$102
Undistributed earnings of foreign subsidiaries	0	75
Investments	5,472	3,663
Other	10	0
Total deferred tax liabilities	5,486	3,840
Deferred tax assets:
Accrued liabilities	178	126
Minimum tax credits	137	66
Foreign tax credit	251	42
Federal loss carryovers	134	0
State losses and credits	250	194
Other	97	91
Total deferred tax assets	1,047	519
Less valuation allowance	206	181
Net deferred tax assets	841	338
Overall net deferred tax liabilities	$4,645	$3,502

Provision_for_Income_Taxes_Rec1

Provision for Income Taxes Reconciliation of Unrecognized Tax Benefits Table (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$66	$58
Additions based on tax positions related to the current year	11	4
Additions for tax positions of prior years	12	18
Reductions for tax positions of prior years	0	-2
Settlement with taxing authorities	0	-12
Balance at end of period	$89	$66

Provision_Benefit_for_Income_T2

Provision (Benefit) for Income Taxes (Details) (USD $)	3 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Feb. 28, 2013	Sep. 30, 2012
Income Tax Contingency [Line Items]
Foreign income (loss) in Income from continuing operations before income taxes		$102		$119		$196
Taxes on undistributed earnings of foreign subsidiaries - net	99	-37		99		0
Tax provision (benefit) in AOCI	-24
Cash payments for income taxes (net of refunds and including discontinued operations)		29		-50		198
Unrecognized tax benefits	66	89		66		58
Reduction of income tax expense, net of federal tax expense, if recognized		86
Total interest and penalties recognized as part of income tax expense (benefit)		8		9		-7
Total interest and penalties accrued as uncertain tax positions	16	24		16
Gain on remeasurement of equity-method investment		2,544	[1]	0	[1]	0	[1]
Minimum tax credits	66	137		66
Deferred Tax Assets, Tax Credit Carryforwards, Foreign		139
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	0	134		0
Deferred Tax Assets, Other Tax Carryforwards		23
Internal Revenue Service (IRS) [Member]
Income Tax Contingency [Line Items]
Tax provision (benefit) from income tax examination									2
Cash payment (refund) from income tax examination								12
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions		45
FederalNetOperatingLossAndCharitableContributionCarryforwards [Member]
Income Tax Contingency [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Domestic		$449
[1]	Items also included in Segment profit (loss). (See Note 19 b Segment Disclosures.)

Earnings_Loss_Per_Common_Share2

Earnings (Loss) Per Common Share from Continuing Operations (Details) (USD $)	12 Months Ended
In Millions, except Share data in Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
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	$2,110	$441	$723
Basic weighted-average shares	719,325	682,948	619,792
Diluted weighted-average shares	723,641	687,185	625,486
Earnings (loss) per common share from continuing operations:
Basic	$2.93	$0.65	$1.17
Diluted	$2.91	$0.64	$1.15
Nonvested restricted stock units [Member]
Effect of dilutive securities:
Incremental common shares attributable to share-based payment arrangements under effects of dilutive securities item	2,234	1,995	2,694
Earnings (loss) per common share from continuing operations (Textuals) [Abstract]
Distributed Earnings	$4	$2	$1
Stock options [Member]
Effect of dilutive securities:
Incremental common shares attributable to share-based payment arrangements under effects of dilutive securities item	2,064	2,149	2,608
Convertible debentures [Member]
Effect of dilutive securities:
Incremental dilutive shares, Convertible debt	18	93	392

EBPs_Obligation_Rollforward_De

EBPs Obligation Rollforward (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Plan, Defined Benefit [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	$1,384	$1,549
Service cost	40	44	39
Interest cost	62	51	55
Plan participants' contributions	0	0
Benefits paid	-86	-87
Medicare Part D subsidy	0	0
Plan amendment	0	0
Actuarial loss (gain)	144	-173
Settlements	-3	0
Curtailments	0	0
Other	3	0
Benefit obligation at end of year	1,544	1,384	1,549
Other Postretirement Benefits [Member]
Change in benefit obligation:
Benefit obligation at beginning of year	213	331
Service cost	2	2	3
Interest cost	10	11	13
Plan participants' contributions	2	6
Benefits paid	-14	-19
Medicare Part D subsidy	0	4
Plan amendment	1	-59
Actuarial loss (gain)	21	-63
Settlements	-1	0
Curtailments	-1	0
Other	0	0
Benefit obligation at end of year	$233	$213	$331

EBP_Asset_rollforward_and_BS_c

EBP Asset rollforward and B.S. classification (Details 1) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits [Member]
Change in plan assets:
Fair value of plan assets at beginning of year	$1,241	$1,071
Actual return on plan assets	78	165
Employer contributions	63	92
Plan participants' contributions	0	0
Benefits paid	-86	-87
Settlements	-3	0
Fair value of plan asets at end of year	1,293	1,241
Funded status - underfunded	-251	-143
Accumulated benefit obligation	1,516	1,359
Underfunded/overfunded status of our pension plans and other postretirement benefit plans
Current liabilities	2	1
Noncurrent liabilities	249	142
Amounts included in accumulated other comprehensive loss:
Prior service (cost) credit	0	0
Net actuarial loss	-593	-491
Other Postretirement Benefits [Member]
Change in plan assets:
Fair value of plan assets at beginning of year	201	175
Actual return on plan assets	13	31
Employer contributions	6	8
Plan participants' contributions	2	6
Benefits paid	-14	-19
Settlements	0	0
Fair value of plan asets at end of year	208	201
Funded status - underfunded	-25	-12
Underfunded/overfunded status of our pension plans and other postretirement benefit plans
Current liabilities	7	8
Noncurrent liabilities	18	4
Amounts included in accumulated other comprehensive loss:
Prior service (cost) credit	17	26
Net actuarial loss	-28	-11
Amounts included in regulatory assets or liabilities associated with Transco and Northwest Pipeline
Prior service credit	30	42
Net actuarial loss	-4	-2
Net regulatory assets (liabilities)	($62)	($44)

EBP_Net_Periodic_Benefit_Cost_

EBP Net Periodic Benefit Cost & OCI (Details 2) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Benefits [Member]
Components of net periodic benefit cost:
Service cost	$40	$44	$39
Interest cost	62	51	55
Expected return on plan assets	-76	-61	-64
Amortization of prior service cost (credit)	0	1	1
Amortization of net actuarial (gain) loss	39	60	53
Net actuarial (gain) loss from settlements and curtailments	1	0	5
Reclassification to regulatory liability	0	0	0
Net periodic benefit cost	66	95	89
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss):
Net actuarial gain (loss)	-142	277	-51
Prior service (cost) credit	0	0	0
Amortization of prior service cost (credit)	0	1	1
Amortization of net actuarial (gain) loss and (gain) loss from settlements and curtailments	40	60	58
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss)	-102	338	8
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	43
Other Postretirement Benefits [Member]
Components of net periodic benefit cost:
Service cost	2	2	3
Interest cost	10	11	13
Expected return on plan assets	-12	-9	-9
Amortization of prior service cost (credit)	-20	-12	-7
Amortization of net actuarial (gain) loss	0	4	8
Net actuarial (gain) loss from settlements and curtailments	-1	0	0
Reclassification to regulatory liability	4	2	0
Net periodic benefit cost	-17	-2	8
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss):
Net actuarial gain (loss)	-18	23	2
Prior service (cost) credit	-1	23	2
Amortization of prior service cost (credit)	-8	-4	-3
Amortization of net actuarial (gain) loss and (gain) loss from settlements and curtailments	1	1	3
Other changes in plan assets and benefit obligations recognized in other comprehensive income (loss)	-26	43	4
Other changes in plan assets and benefit obligations recognized in regulatory (assets) liabilities:
Net actuarial gain (loss) recognized in regulatory liabilities (assets)	-2	62	13
Prior service credit (cost) recognized in regulatory liabilities (assets)	0	36	4
Amortization of net actuarial loss (gain) from regulatory assets (liabilities)	0	3	5
Amortization of prior service cost (credit) from regulatory assets (liabilities)	-12	-8	-4
Amounts included in accumulated other comprehensive income (loss):
Prior service cost (credit) expected to be amortized in next fiscal year	-7
Net actuarial (gain) loss expected to be amortized in next fiscal year	-1
Amounts included in regulatory assets or liabilities associated with Transco and Northwest Pipeline
Prior service cost (credit) expected to be amortized in next fiscal year	-10
Net actuarial (gain) loss expected to be amortized in next fiscal year	$0

EBP_Key_Assumptions_Details_3

EBP Key Assumptions (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Benefits [Member]
Weighted average assumptions utilized to determine benefit obligations
Discount rate	3.96%	4.68%
Rate of compensation increase	4.62%	4.56%
Weighted average assumptions utilized to determine net periodic benefit cost
Discount rate	4.68%	3.43%	3.98%
Expected long-term rate of return on plan assets	6.85%	5.90%	6.30%
Rate of compensation increase	4.56%	4.57%	4.52%
Other Postretirement Benefits [Member]
Weighted average assumptions utilized to determine benefit obligations
Discount rate	4.12%	4.80%
Weighted average assumptions utilized to determine net periodic benefit cost
Discount rate	4.80%	3.97%	4.22%
Expected long-term rate of return on plan assets	6.11%	5.26%	5.71%
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	9
Effect on other postretirement benefit obligation, Point decrease	-7
Health care cost trend rate assumed for next fiscal year	6.90%
Direction and pattern of change for assumed health care cost trend rate	decreases
Ultimate health care cost trend rate	5.00%
Year that rate reaches ultimate trend rate	2023

EBP_Plan_Assets_Details_4

EBP Plan Assets (Details 4) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
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	15.00%
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	$0	0
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	0	0
Equities - International small cap [Member] | Commingled investment funds - equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Maximum Percentage In Emerging Markets	15.00%
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Maximum Time Span To Require Redemption Fee	180 days
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Redemption Fee	1.50%
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period	10 days
Equities - Emerging markets value [Member] | Commingled investment funds - equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period	10 days
Equities - Emerging markets growth [Member] | Commingled investment funds - equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period	15 days
Equities - International developed markets large cap value [Member] | Commingled investment funds - equities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Notice Period	10 days
Fixed income - Corporate bonds [Member] | Commingled investment funds - fixed income [Member]
Defined Benefit Plan Disclosure [Line Items]
Maximum allocation to BBB rated securities	10.00%
Target approximate duration in years	20 years
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of active investment managers managing plan funds	10
Number of passive investment managers managing plan funds	1
Fair Value, Assets, Level 1 to Level 2 Transfers, Amount	0
Fair Value, Assets, Level 2 to Level 1 Transfers, Amount	0
Fair values of plan assets
Total assets at fair value	1,293	1,241	1,071
Pension Benefits [Member] | Equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets target allocation range, minimum	54.00%
Plan assets target allocation range, maximum	66.00%
Pension Benefits [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets target allocation range, minimum	36.00%
Plan assets target allocation range, maximum	44.00%
Weighted average duration of fixed income security portfolio1	6 years	6 years
Pension Benefits [Member] | U.S. equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets target allocation range, minimum	37.00%
Plan assets target allocation range, maximum	45.00%
Pension Benefits [Member] | International equity securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Plan assets target allocation range, minimum	17.00%
Plan assets target allocation range, maximum	21.00%
Pension Benefits [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	25	23
Pension Benefits [Member] | U.S. large cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	221	211
Pension Benefits [Member] | U.S. small cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	139	146
Pension Benefits [Member] | International developed markets large cap growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	60	59
Pension Benefits [Member] | Preferred stock [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value		2
Pension Benefits [Member] | Equities - U.S. large cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	189	179
Pension Benefits [Member] | Equities - International small cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	24	24
Pension Benefits [Member] | Equities - Emerging markets value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	27	34
Pension Benefits [Member] | Equities - Emerging markets growth [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	19	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	100
Pension Benefits [Member] | Fixed income - Corporate bonds [Member] | Commingled investment funds - fixed income [Member]
Fair values of plan assets
Total assets at fair value	163	140
Pension Benefits [Member] | U.S. Treasury securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	31	30
Pension Benefits [Member] | Mortgage-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	65	67
Pension Benefits [Member] | Corporate bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	222	200
Pension Benefits [Member] | Insurance company investment contracts and other [Member]
Fair values of plan assets
Total assets at fair value	7	7
Pension Benefits [Member] | Level 1 [Member]
Fair values of plan assets
Total assets at fair value	416	412
Pension Benefits [Member] | Level 1 [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	25	23
Pension Benefits [Member] | Level 1 [Member] | U.S. large cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	221	211
Pension Benefits [Member] | Level 1 [Member] | U.S. small cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	139	146
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	0
Pension Benefits [Member] | Level 1 [Member] | Preferred stock [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value		2
Pension Benefits [Member] | Level 1 [Member] | Equities - U.S. large cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 1 [Member] | Equities - International small cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 1 [Member] | Equities - Emerging markets value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 1 [Member] | Equities - Emerging markets growth [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 1 [Member] | Equities - International developed markets large cap value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 1 [Member] | Fixed income - Corporate bonds [Member] | Commingled investment funds - fixed income [Member]
Fair values of plan assets
Total assets at fair value	0	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	31	30
Pension Benefits [Member] | Level 1 [Member] | Mortgage-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	877	829
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	59
Pension Benefits [Member] | Level 2 [Member] | Preferred stock [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value		0
Pension Benefits [Member] | Level 2 [Member] | Equities - U.S. large cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	189	179
Pension Benefits [Member] | Level 2 [Member] | Equities - International small cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	24	24
Pension Benefits [Member] | Level 2 [Member] | Equities - Emerging markets value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	27	34
Pension Benefits [Member] | Level 2 [Member] | Equities - Emerging markets growth [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	19	19
Pension Benefits [Member] | Level 2 [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	100
Pension Benefits [Member] | Level 2 [Member] | Fixed income - Corporate bonds [Member] | Commingled investment funds - fixed income [Member]
Fair values of plan assets
Total assets at fair value	163	140
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] | Mortgage-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	65	67
Pension Benefits [Member] | Level 2 [Member] | Corporate bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	222	200
Pension Benefits [Member] | Level 2 [Member] | Insurance company investment contracts and other [Member]
Fair values of plan assets
Total assets at fair value	7	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	0
Pension Benefits [Member] | Level 3 [Member] | Preferred stock [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value		0
Pension Benefits [Member] | Level 3 [Member] | Equities - U.S. large cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | Equities - International small cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | Equities - Emerging markets value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | Equities - Emerging markets growth [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | Equities - International developed markets large cap value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Pension Benefits [Member] | Level 3 [Member] | Fixed income - Corporate bonds [Member] | Commingled investment funds - fixed income [Member]
Fair values of plan assets
Total assets at fair value	0	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] | Mortgage-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	208	201	175
Other Postretirement Benefits [Member] | Fixed income securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average duration of fixed income security portfolio1	5 years	5 years
Other Postretirement Benefits [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	13	13
Other Postretirement Benefits [Member] | U.S. large cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	53	52
Other Postretirement Benefits [Member] | U.S. small cap [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	28	29
Other Postretirement Benefits [Member] | International developed markets large cap growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	15	15
Other Postretirement Benefits [Member] | Emerging markets growth [Member] | Equity securities [Member]
Fair values of plan assets
Total assets at fair value	3	2
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	19	18
Other Postretirement Benefits [Member] | Equities - International small cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	2	2
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	4
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	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	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	16	14
Other Postretirement Benefits [Member] | U.S. Treasury securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	3	3
Other Postretirement Benefits [Member] | Government and municipal bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	11	10
Other Postretirement Benefits [Member] | Mortgage-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	7	7
Other Postretirement Benefits [Member] | Corporate bonds [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	23	20
Other Postretirement Benefits [Member] | Level 1 [Member]
Fair values of plan assets
Total assets at fair value	98	98
Other Postretirement Benefits [Member] | Level 1 [Member] | Cash management fund [Member]
Fair values of plan assets
Total assets at fair value	13	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	53	52
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	28	29
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	0	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	1	1
Other Postretirement Benefits [Member] | Level 1 [Member] | Equities - U.S. large cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 1 [Member] | Equities - International small cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 1 [Member] | Equities - Emerging markets value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 1 [Member] | Equities - Emerging markets growth [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 1 [Member] | Equities - International developed markets large cap value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 1 [Member] | Fixed income - Corporate bonds [Member] | Commingled investment funds - fixed income [Member]
Fair values of plan assets
Total assets at fair value	0	0
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	3	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-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	110	103
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	15	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	2	1
Other Postretirement Benefits [Member] | Level 2 [Member] | Equities - U.S. large cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	19	18
Other Postretirement Benefits [Member] | Level 2 [Member] | Equities - International small cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	2	2
Other Postretirement Benefits [Member] | Level 2 [Member] | Equities - Emerging markets value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	3	4
Other Postretirement Benefits [Member] | Level 2 [Member] | Equities - Emerging markets growth [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	2	2
Other Postretirement Benefits [Member] | Level 2 [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	10
Other Postretirement Benefits [Member] | Level 2 [Member] | Fixed income - Corporate bonds [Member] | Commingled investment funds - fixed income [Member]
Fair values of plan assets
Total assets at fair value	16	14
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	11	10
Other Postretirement Benefits [Member] | Level 2 [Member] | Mortgage-backed securities [Member] | Fixed income securities [Member]
Fair values of plan assets
Total assets at fair value	7	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	23	20
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] | Equities - U.S. large cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | Equities - International small cap [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | Equities - Emerging markets value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | Equities - Emerging markets growth [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | Equities - International developed markets large cap value [Member] | Commingled investment funds - equities [Member]
Fair values of plan assets
Total assets at fair value	0	0
Other Postretirement Benefits [Member] | Level 3 [Member] | Fixed income - Corporate bonds [Member] | Commingled investment funds - fixed income [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-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_Cont

EBP Benefit Pymts & Defined Contribution Plans (Details 6) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Expected benefit payments
Employer's contributions charged to expense under defined contribution plans	$39	$27	$25
Other Postretirement Benefits [Member]
Expected benefit payments
2015	14
2016	15
2017	15
2018	16
2019	13
2020-2024	70
Expected total plans contribution, approximate	7
Pension Benefits [Member]
Expected benefit payments
2015	100
2016	107
2017	107
2018	110
2019	117
2020-2024	609
Expected total plans contribution, approximate	62
Nonqualified Pension Benefits - Supplemental Employee Retirement Benefits [Member]
Expected benefit payments
Expected total plans contribution, approximate	2
Tax-qualified Pension Benefits [Member]
Expected benefit payments
Expected total plans contribution, approximate	$60

Inventories_Details

Inventories (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Inventory, Net [Abstract]
Natural gas liquids, olefins, and natural gas in underground storage	$150	$111
Materials, supplies, and other	81	83
Inventories, Total	$231	$194

Property_Plant_and_Equipment_D

Property, Plant, and Equipment (Details PPE) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012
Property, Plant, and Equipment
Total property, plant, and equipment, at cost	$36,435		$25,823
Accumulated depreciation and amortization	-8,354		-7,613
Property, plant, and equipment - net	28,081		18,210
Depreciation and amortization	967		752	712
Nonregulated [Member] | Natural gas gathering and processing facilities [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost	18,749		9,185
Nonregulated [Member] | Natural gas gathering and processing facilities [Member] | Minimum [Member]
Property, Plant, and Equipment
Property, Plant and Equipment, Useful Life	5 years	[1]
Nonregulated [Member] | Natural gas gathering and processing facilities [Member] | Maximum [Member]
Property, Plant, and Equipment
Property, Plant and Equipment, Useful Life	40 years	[1]
Nonregulated [Member] | Construction in Progress [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost	2,648		3,123
Nonregulated [Member] | Other Capitalized Property Plant and Equipment [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost	1,850		1,316
Nonregulated [Member] | Other Capitalized Property Plant and Equipment [Member] | Minimum [Member]
Property, Plant, and Equipment
Property, Plant and Equipment, Useful Life	3 years	[1]
Nonregulated [Member] | Other Capitalized Property Plant and Equipment [Member] | Maximum [Member]
Property, Plant, and Equipment
Property, Plant and Equipment, Useful Life	45 years	[1]
Regulated [Member] | Natural gas transmission facilities [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost	10,867		10,633
Regulated [Member] | Natural gas transmission facilities [Member] | Minimum [Member]
Property, Plant, and Equipment
Property, Plant, and Equipment, Depreciation Rate	1.20%	[1]
Regulated [Member] | Natural gas transmission facilities [Member] | Maximum [Member]
Property, Plant, and Equipment
Property, Plant, and Equipment, Depreciation Rate	6.97%	[1]
Regulated [Member] | Construction in Progress [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost	985		273
Regulated [Member] | Other Capitalized Property Plant and Equipment [Member]
Property, Plant, and Equipment
Total property, plant, and equipment, at cost	1,336		1,293
Regulated [Member] | Other Capitalized Property Plant and Equipment [Member] | Minimum [Member]
Property, Plant, and Equipment
Property, Plant, and Equipment, Depreciation Rate	1.35%	[1]
Regulated [Member] | Other Capitalized Property Plant and Equipment [Member] | Maximum [Member]
Property, Plant, and Equipment
Property, Plant, and Equipment, Depreciation Rate	33.33%	[1]
Regulated [Member] | Excess Of Original Cost Of Regulated Facilities [Member]
Property, Plant, and Equipment
Property, plant, and equipment - net	$746		$785
Period of straight-line amortization	40 years
[1]	Estimated useful life and depreciation rates are presented as of DecemberB 31, 2014. Depreciation rates for regulated assets are prescribed by the FERC.

Property_Plant_and_Equipment_D1

Property, Plant, and Equipment (Details ARO) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Asset Retirement Obligations
Asset Retirement Obligations, Noncurrent	$791		$497
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Beginning balance	561		579
Liabilities incurred	101		8
Liabilities settled	-21	[1]	-31	[1]
Accretion expense	44		53
Revisions	146	[2]	-48	[2]
Ending balance	831		561
Charges related to leak at underground storage facility [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Liabilities settled	-7		-25
Revisions			9
Asset Retirement Obligation Costs [Member]
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Transco's annual funding commitment for ARO	$36
[1]	For 2014 and 2013 liabilities settled include $7 million and $25 million, respectively, related to the abandonment of certain of Transcobs 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 life of the assets. 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 2013 revision primarily reflects increases in the estimated remaining useful life of the assets. The 2013 revision also includes an increase of $9 million related to changes in the timing and method of abandonment on certain of Transcobs natural gas storage caverns that were associated with a leak in 2010.

Goodwill_and_Other_Intangible_2

Goodwill and Other Intangible assets Goodwill (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Goodwill	$1,120	$646
Goodwill, Acquired During Period	474
Williams Partners [Member]
Goodwill [Line Items]
Goodwill	646	646
Goodwill, Acquired During Period	0
Access Midstream [Member]
Goodwill [Line Items]
Goodwill	474	0
Goodwill, Acquired During Period	$474

Goodwill_and_Other_Intangible_3

Goodwill and Other Intangible assets Other Intangible Assets (Details) (USD $)	12 Months Ended			6 Months Ended	2 Months Ended	4 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 02, 2014	Feb. 17, 2012	Apr. 27, 2012
Finite-Lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$209	$60	$43
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	357
Finite-Lived Intangible Assets, Amortization Expense, Year Two	357
Finite-Lived Intangible Assets, Amortization Expense, Year Three	357
Finite-Lived Intangible Assets, Amortization Expense, Year Four	357
Finite-Lived Intangible Assets, Amortization Expense, Year Five	357
Contractual customer relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	10,763	1,749
Finite-Lived Intangible Assets, Accumulated Amortization	($310)	($105)
Access Midstream Partners 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				17 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

Accrued_Liabilities_Details

Accrued Liabilities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Accrued Liabilities, Current [Abstract]
Interest on debt	$268	$167
Employee costs	167	127
Deferred income	82	47
Estimated rate refund liability	1	98
Asset retirement obligations	40	64
Other, including other loss contingencies	342	294
Total accrued liabilities	$900	$797

LongTerm_Debt_Details_1

Long-Term Debt (Details 1) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Nov. 15, 2013	Mar. 04, 2014	Jun. 27, 2014	Jun. 24, 2014
In Millions, unless otherwise specified
Long-term Debt
Capital lease obligations	$5		$1
Net unamortized debt premium (discount)	187	[1]	-37	[1]
Total long-term debt, including current portion	20,892		11,354
Long-term debt due within one year	-4		-1
Long-term debt	20,888		11,353
Transcontinental Gas Pipe Line Company, LLC [Member] | 6.4% Senior Unsecured Notes due 2016 [Member]
Long-term Debt
Long-term debt	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	7.13%
Williams Partners L.P. [Member]
Long-term Debt
Credit facility loans	0
Williams Partners L.P. [Member] | 3.8% Senior Unsecured Notes due 2015 [Member]
Long-term Debt
Long-term debt	750	[2]	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	4.13%
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] | 3.35% 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] | 4.5% Senior Unsecured Notes due 2023 [Member]
Long-term Debt
Long-term debt	600		600
Long-term debt interest rate	4.50%				4.50%
Williams Partners L.P. [Member] | 4.3% Senior Unsecured Notes Due 2024 [Member]
Long-term Debt
Long-term debt	1,000		0
Long-term debt interest rate	4.30%					4.30%
Williams Partners L.P. [Member] | 3.9% Senior Unsecured Notes due 2025 [Member]
Long-term Debt
Long-term debt	750		0
Long-term debt interest rate	3.90%						3.90%
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%				5.80%
Williams Partners L.P. [Member] | 5.4% Senior Unsecured Notes Due 2044 [Member]
Long-term Debt
Long-term debt	500		0
Long-term debt interest rate	5.40%					5.40%
Williams Partners L.P. [Member] | 4.9% Senior Unsecured Notes due 2045 [Member]
Long-term Debt
Long-term debt	500		0
Long-term debt interest rate	4.90%						4.90%
The Williams Companies, Inc. [Member]
Long-term Debt
Credit facility loans	370		0
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	7.88%
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		0
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		0
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%
Access Midstream Partners L.P. [Member]
Long-term Debt
Credit facility loans	640	[3]	0	[3]
Access Midstream Partners L.P. [Member] | 5.875% Senior Unsecured Notes due 2021 [Member]
Long-term Debt
Long-term debt	750	[3]	0	[3]
Long-term debt interest rate	5.88%
Access Midstream Partners L.P. [Member] | 6.125% Senior Unsecured Notes due 2022 [Member]
Long-term Debt
Long-term debt	750	[3]	0	[3]
Long-term debt interest rate	6.13%
Access Midstream Partners L.P. [Member] | 4.875% Senior Unsecured Notes due 2023 [Member]
Long-term Debt
Long-term debt	1,400	[3]	0	[3]
Long-term debt interest rate	4.88%
Access Midstream Partners L.P. [Member] | 4.875% Senior Unsecured Notes due 2024 [Member]
Long-term Debt
Long-term debt	$750	[3]	$0	[3]
Long-term debt interest rate	4.88%
[1]	Includes premium related to the fair value of ACMP debt. See Note 2 b Acquisitions.
[2]	Presented as long-term debt due to the merged partnershipbs intent and ability to refinance.
[3]	See Note 2 b Acquisitions.

LongTerm_Debt_Maturities_Detai

Long-Term Debt Maturities (Details 2) (USD $)	Dec. 31, 2014
In Millions, unless otherwise specified
Aggregate minimum maturities of long-term debt
2015	$0
2016	375
2017	785
2018	1,510
2019	$32

LongTerm_Debt_Issuances_and_Re

Long-Term Debt Issuances and Retirements (Details 3) (USD $)	0 Months Ended
In Millions, unless otherwise specified	Feb. 15, 2015	Dec. 31, 2014	Jun. 24, 2014	Jun. 27, 2014	Mar. 04, 2014	Nov. 15, 2013
The Williams Companies, Inc. [Member] | 4.55% Senior Unsecured Notes due 2024 [Member]
Debt Instrument [Line Items]
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 face amount			650
Long-term debt interest rate		5.75%	5.75%
Williams Partners L.P. [Member] | 3.8% Senior Unsecured Notes due 2015 [Member]
Debt Instrument [Line Items]
Long-term debt interest rate		3.80%
Williams Partners L.P. [Member] | 3.8% Senior Unsecured Notes due 2015 [Member] | Subsequent Event [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%		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%		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%			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%			5.40%
Williams Partners L.P. [Member] | 4.5% Senior Unsecured Notes due 2023 [Member]
Debt Instrument [Line Items]
Long-term debt face amount						600
Long-term debt interest rate		4.50%				4.50%
Williams Partners L.P. [Member] | 5.8% Senior Unsecured Notes due 2043 [Member]
Debt Instrument [Line Items]
Long-term debt face amount						$400
Long-term debt interest rate		5.80%				5.80%

Credit_Facilities_and_Commerci

Credit Facilities and Commercial Paper (Details 4) (USD $)	0 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Feb. 02, 2015	Dec. 31, 2014		Dec. 31, 2013		Feb. 24, 2015	Feb. 03, 2015
Credit Facility and Commercial Paper [Line Items]
Commercial paper, outstanding		$798		$225
Williams Companies, Inc. [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity		1,500
Credit facility, loans outstanding		370		0
Additional amount by which credit facility can be increased		500
Williams Companies, Inc. [Member] | Subsequent Event [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity	1,500
Credit facility, loans outstanding						0
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] | Letters of credit [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity		700
Credit facility, letters of credit outstanding		0
Williams Companies, Inc. [Member] | Letters of credit [Member] | Subsequent Event [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		15
Williams Companies, Inc. [Member] | Swing line advances [Member] | Subsequent Event [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity	50
Williams Partners L.P. [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity		2,500
Credit facility, loans outstanding		0
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, capacity	3,500
Credit facility, loans outstanding						1,300
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 Partners L.P. [Member] | Rate addition to federal funds effective rate [Member] | Subsequent Event [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] | Subsequent Event [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, basis spread on variable rate	1.00%
Williams Partners L.P. [Member] | Commercial paper [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity		2,000
Commercial paper, outstanding		798		225
Commercial paper, weighted average interest rate		0.92%		0.42%
Commercial paper, maximum maturity		397 days
Williams Partners L.P. [Member] | Commercial paper [Member] | Subsequent Event [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity	3,000
Commercial paper, outstanding						1,800
Williams Partners L.P. [Member] | Letters of credit [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity		1,300
Credit facility, letters of credit outstanding		0
Williams Partners L.P. [Member] | Letters of credit [Member] | Subsequent Event [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		1
Williams Partners L.P. [Member] | Swing line advances [Member] | Subsequent Event [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity	150
Williams Partners L.P. [Member] | Short-term facility [Member] | Subsequent Event [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity							1,500
Transcontinental Gas Pipe Line Company, LLC [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity		500
Transcontinental Gas Pipe Line Company, LLC [Member] | Subsequent Event [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
Northwest Pipeline LLC [Member] | Subsequent Event [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity	500
Maximum ratio of debt to capitalization	65.00%
Access Midstream Partners Lp [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity		1,750
Credit facility, loans outstanding		640	[1]	0	[1]
Additional amount by which credit facility can be increased		250
Access Midstream Partners Lp [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%
Access Midstream Partners Lp [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%
Access Midstream Partners Lp [Member] | Rate plus a margin [Member] | Minimum [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, basis spread on variable rate		0.50%
Access Midstream Partners Lp [Member] | Rate plus a margin [Member] | Maximum [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, basis spread on variable rate		1.50%
Access Midstream Partners Lp [Member] | Eurodollar rate plus a margin [Member] | Minimum [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, basis spread on variable rate		1.50%
Access Midstream Partners Lp [Member] | Eurodollar rate plus a margin [Member] | Maximum [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, basis spread on variable rate		2.50%
Access Midstream Partners Lp [Member] | Leverage-based pricing grid [Member] | Minimum [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, unused capacity commitment fee percentage		0.25%
Access Midstream Partners Lp [Member] | Leverage-based pricing grid [Member] | Maximum [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, unused capacity commitment fee percentage		0.38%
Access Midstream Partners Lp [Member] | Ratings-based pricing grid [Member] | Minimum [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, unused capacity commitment fee percentage		0.15%
Access Midstream Partners Lp [Member] | Ratings-based pricing grid [Member] | Maximum [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, unused capacity commitment fee percentage		0.30%
Access Midstream Partners Lp [Member] | Letters of credit [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity		200
Credit facility, letters of credit outstanding		2
Access Midstream Partners Lp [Member] | Swing line advances [Member]
Credit Facility and Commercial Paper [Line Items]
Credit facility, capacity		100
Credit facility, loans outstanding		$0
[1]	See Note 2 b Acquisitions.

Cash_Payments_For_Interest_Net

Cash Payments For Interest (Net of Amounts Capitalized) (Details 5) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Disclosure [Abstract]
Cash payments for interest (net of amounts capitalized)	$681	$472	$479

Restricted_Net_Assets_of_Subsi

Restricted Net Assets of Subsidiaries (Details 6) (USD $)	Dec. 31, 2014
In Billions, unless otherwise specified
Debt Disclosure [Abstract]
Amount of restricted net assets for consolidated and unconsolidated subsidiaries	$15
Restricted net assets threshold	25.00%

LeasesLessee_Details_7

Leases-Lessee (Details 7) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Future minimum annual rentals under noncancelable operating leases
2015	$83
2016	71
2017	55
2018	41
2019	33
Therafter	129
Total	412
Operating leases [Abstract]
Total rent expense	$109	$58	$56

Stockholders_Equity_Details

Stockholders' Equity (Details) (USD $)	0 Months Ended	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Jun. 23, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stockholders's Equity (Textuals) [Abstract]
Proceeds from Issuance of Common Stock	$3,378	$3,416	$18	$2,550
Common Stock, Dividends, Per Share, Declared		$1.96	$1.44	$1.20
Stock Issued During Period, Shares, New Issues	61
Equity Issuance, Per Share Amount	$57
Common Units Sold In Offering	8
Statement [Line Items]
Total, Beginning Balance		-164
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		-178
Other comprehensive income (loss)		-176	198	27
Changes in ownership of consolidated subsidiaries, net		44	-243
Total, Ending Balance		-341	-164
Reclassifications Out Of Accumulated Other Comprehensive Income [Abstract]
Reclassifications before income tax		-3,584	-1,080	-1,289
Provision (benefit) for income taxes		-1,249	-401	-360
Reclassification out of Accumulated Other Comprehensive Income [Member]
Statement [Line Items]
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		21
Reclassifications Out Of Accumulated Other Comprehensive Income [Abstract]
Provision (benefit) for income taxes		-12
Reclassifications during the period		21
Cash flow hedging activities [Member]
Statement [Line Items]
Total, Beginning Balance		-1
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0
Other comprehensive income (loss)		0
Changes in ownership of consolidated subsidiaries, net		0
Total, Ending Balance		-1
Foreign currency translation [Member]
Statement [Line Items]
Total, Beginning Balance		128
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		-77
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		0
Other comprehensive income (loss)		-77
Changes in ownership of consolidated subsidiaries, net		-20
Total, Ending Balance		31
Pension and other postretirement benefits [Member]
Statement [Line Items]
Total, Beginning Balance		-291
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		-101
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax		21
Other comprehensive income (loss)		-80
Changes in ownership of consolidated subsidiaries, net		0
Total, Ending Balance		-371
Pension and other postretirement benefits [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassifications Out Of Accumulated Other Comprehensive Income [Abstract]
Amortization of prior service cost (credit) included in net periodic benefit cost		-8
Amortization of actuarial (gain) loss included in net periodic benefit cost		41
Reclassifications before income tax		33
Accumulated Other Comprehensive Income (Loss) [Member]
Statement [Line Items]
Other comprehensive income (loss)		-157	198	27
Changes in ownership of consolidated subsidiaries, net		($20)	$0

EquityBased_Compensation_Detai

Equity-Based Compensation (Details) (USD $)	12 Months Ended					6 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2014		22-May-14	20-May-10	17-May-07
Williams Companies Incentive Plan [Member]
Equity-Based Compensation (Textuals) [Abstract]
Shares reserved for issuance	31,000,000					31,000,000		10,000,000	11,000,000	19,000,000
Shares available for future grants	22,000,000					22,000,000
Equity-based compensation expense	$44,000,000		$37,000,000		$36,000,000
Tax benefit from equity-based compensation expense	17,000,000		14,000,000		13,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Abstract]
Unrecognized equity-based compensation expense	63,000,000					63,000,000
Estimated forfeitures under employee equity-based awards	2,000,000					2,000,000
Unrecognized equity-based compensation expense, Weighted-average period of recognition in years	2 years
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					4,000,000
Rollforward of stock option activity and related information
Options Outstanding, Beginning Balance	6,700,000
Options, Weighted Average Exercise Price, Beginning Balance	$21.82
Options, Granted	800,000
Options, Weighted Average Exercise Price, Granted	$41.76
Options, Exercised	-1,700,000
Options, Weighted Average Exercise Price, Exercised	$17.93
Options Outstanding, Ending Balance	5,800,000		6,700,000			5,800,000
Options, Weighted Average Exercise Price, Ending Balance	$25.86		$21.82			$25.86
Options, Aggregate Intrinsic Value, Ending Balance	110,000,000					110,000,000
Options Exercisable at Period End	4,000,000					4,000,000
Options, Weighted Average Exercise Price, Exercisable at Period End	$21.25					$21.25
Options, Aggregate Intrinsic Value, Exercisable at Period End	96,000,000					96,000,000
Total intrinsic value of stock options exercised	48,000,000		23,000,000		69,000,000
Tax benefit realized from stock options exercised	18,000,000		9,000,000		25,000,000
Cash received from stock option exercised	31,000,000		13,000,000		50,000,000
Stock Options Outstanding, Weighted Average Remaining Contractual Life	5 years 5 months
Stock Options Exercisable, Weighted Average Remaining Contractual Life	4 years 2 months
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	$7.50		$5.94		$5.65
Weighted-average assumptions:
Dividend yield	4.20%		4.30%		3.70%
Volatility	28.00%		29.70%		30.00%
Risk-free interest rate	2.20%		1.40%		1.30%
Expected life (years)	6 years 6 months		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	59,000,000					59,000,000
Rollforward of nonvested restricted stock unit activity and related information
Restricted Stock Units, Nonvested shares, Beginning Balance	3,500,000
Restricted Stock Units, Nonvested, Weighted-Average Fair Value, Beginning Balance	$27.16	[1]
Restricted Stock Units, Granted	1,400,000
Weighted-average grant date fair value of restricted stock units granted during the year, per share	$42.79	[1]	$30.43		$20.61
Restricted Stock Units, Forfeited	-100,000
Restricted Stock Units, Forfeited, Weighted-Average Fair Value	$29.57	[1]
Restricted Stock Units, Vested, Shares	-1,200,000
Restricted Stock Units, Vested, Weighted-Average Fair Value	$24.07	[1]
Restricted Stock Units, Nonvested shares, Ending Balance	3,600,000		3,500,000			3,600,000
Restricted Stock Units, Nonvested, Weighted-Average Fair Value, Ending Balance	$33.90	[1]	$27.16	[1]		$33.90	[1]
Restricted Stock Units, Vested in Period, Fair Value	27,000,000		27,000,000		22,000,000
Williams Companies Incentive Plan [Member] | Performance Shares [Member]
Rollforward of nonvested restricted stock unit activity and related information
Share Based Compensation Arrangement By Share Based Payment Award Duration Of Postvesting Restriction On Sale	2 years
Performance based nonvested restricted stock units as a percent of total nonvested restricted stock units outstanding	39.00%					39.00%
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%					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%					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	1,800,000					1,800,000
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	193,000
Average price of shares purchased	$35.33
Access Midstream Partners Long Term Incentive Plan [Member] | Nonvested Restricted Stock Units [Member]
Equity-Based Compensation (Textuals) [Abstract]
Equity-based compensation expense						11,000,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized [Abstract]
Unrecognized equity-based compensation expense - Restricted Stock Units	65,000,000					65,000,000
Estimated forfeitures under employee equity-based awards	$6,000,000					$6,000,000
Unrecognized equity-based compensation expense, Weighted-average period of recognition in years						2 years 4 months
Rollforward of nonvested restricted stock unit activity and related information
Restricted Stock Units, Granted	1,300,000
Weighted-average grant date fair value of restricted stock units granted during the year, per share						$59.67
Restricted Stock Units, Forfeited						0
Restricted Stock Units, Forfeited, Weighted-Average Fair Value						$63.89
Restricted Stock Units, Vested, Shares						0
Restricted Stock Units, Vested, Weighted-Average Fair Value						$63.75
Restricted Stock Units, Nonvested shares, Ending Balance	1,300,000					1,300,000
Restricted Stock Units, Nonvested, Weighted-Average Fair Value, Ending Balance	$59.35					$59.35
Access Midstream 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
Access Midstream 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 or the grant-date market price less dividends projected to be paid over the vesting period. Restricted stock units generally vest after three years.

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	3 Months Ended		12 Months Ended					3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2012	Jun. 30, 2014	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2014
Additional disclosure:
Fair Value, Level 1 to level 2 Transfers, Amount			$0		$0			$0
Fair Value, Level 2 to level 1 Transfers, Amount			0		0			0
Former Venezuela Operations [Member]
Additional disclosure:
Notes Receivable, Fair Value Disclosure	88
Proceeds from Legal Settlements	98
Wpx Energy Inc [Member]
Additional disclosure:
Proceeds from Legal Settlements		42
Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax		7
Carrying Amount [Member]
Additional disclosure:
Notes receivable and other			30		77			30
Long-term debt, including current portion			-20,887	[1]	-11,353	[1]		-20,887	[1]
Guarantee			-31		-32			-31
Carrying Amount [Member] | Former Venezuela Operations [Member]
Additional disclosure:
Notes Receivable, Fair Value Disclosure			25					25
Fair Value [Member]
Additional disclosure:
Notes receivable and other			57		140			57
Long-term debt, including current portion			-21,131	[1]	-11,971	[1]		-21,131	[1]
Guarantee			-27		-29			-27
Fair Value [Member] | Former Venezuela Operations [Member]
Additional disclosure:
Notes Receivable, Fair Value Disclosure			53					53
Level 1 [Member]
Additional disclosure:
Notes receivable and other			0		1			0
Long-term debt, including current portion			0	[1]	0	[1]		0	[1]
Guarantee			0		0			0
Level 2 [Member]
Additional disclosure:
Notes receivable and other			4		6			4
Long-term debt, including current portion			-21,131	[1]	-11,971	[1]		-21,131	[1]
Guarantee			-27		-29			-27
Level 3 [Member]
Additional disclosure:
Notes receivable and other			53		133			53
Long-term debt, including current portion			0	[1]	0	[1]		0	[1]
Guarantee			0		0			0
Fair Value, Measurements, Recurring [Member] | Carrying Amount [Member]
Measured on a recurring basis:
ARO Trust investments			48		33			48
Fair Value, Measurements, Recurring [Member] | Carrying Amount [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis:
Energy derivatives assets			3		3			3
Energy derivative liabilities			-2		-3			-2
Fair Value, Measurements, Recurring [Member] | Fair Value [Member]
Measured on a recurring basis:
ARO Trust investments			48		33			48
Fair Value, Measurements, Recurring [Member] | Fair Value [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis:
Energy derivatives assets			3		3			3
Energy derivative liabilities			-2		-3			-2
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Measured on a recurring basis:
ARO Trust investments			48		33			48
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis:
Energy derivatives assets			1		0			1
Energy derivative liabilities			0		0			0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Measured on a recurring basis:
ARO Trust investments			0		0			0
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Not Designated as Hedging Instrument [Member]
Measured on a recurring basis:
Energy derivatives assets			0		0			0
Energy derivative liabilities			0		-1			0
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]
Measured on a recurring basis:
ARO Trust investments			0		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		3			2
Energy derivative liabilities			-2		-2			-2
Wiltel Guarantee [Member]
Additional disclosure:
Guarantor Obligations, Maximum Exposure, Undiscounted			34					34
Williams Partners [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Additional disclosure:
Assets Held-for-sale, Long Lived, Fair Value Disclosure			32					32
Impairment of Long-Lived Assets to be Disposed of			27
Access Midstream [Member]
Additional disclosure:
Impairment of Long-Lived Assets to be Disposed of			12		0		0
Access Midstream [Member] | Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]
Additional disclosure:
Assets Held-for-sale, Long Lived, Fair Value Disclosure			1					1
Impairment of Long-Lived Assets to be Disposed of								$12
[1]	Excludes capital leases

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details Guarantees and Credit Risk) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts and notes receivable
Receivables by product or service	1,139	674
Customer Concentration Risk [Member] | Accounts receivable [Member]
Accounts and notes receivable
Receivables by product or service	308
Customer Concentration Risk [Member] | Accounts receivable [Member] | Williams Partners [Member]
Accounts and notes receivable
Number Of Major Customers - Receivables	1
Revenues
Number Of Major Customers - Revenues	1
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Williams Partners [Member]
Accounts and notes receivable
Number Of Major Customers - Receivables			1
Revenues
Number Of Major Customers - Revenues			1
Consolidated revenue, major customer, percentage	5.00%	9.00%	14.00%
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Access Midstream [Member]
Revenues
Consolidated revenue, major customer, percentage	9.00%
NGLs, natural gas, and related products and services [Member]
Accounts and notes receivable
Receivables by product or service	730	341
Transportation of natural gas and related products [Member]
Accounts and notes receivable
Receivables by product or service	175	193
Income tax receivable [Member]
Accounts and notes receivable
Receivables by product or service	167	74
Other Receivable [Member]
Accounts and notes receivable
Receivables by product or service	67	66
Wiltel Guarantee [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	34
Wpx Energy Inc [Member]
Guarantor Obligations [Line Items]
Guarantor Obligations, Maximum Exposure, Undiscounted	44

Contingent_Liabilities_and_Com1

Contingent Liabilities and Commitments (Details Textual) (USD $)	0 Months Ended
	Sep. 12, 2014	Dec. 31, 2014	Dec. 01, 2014	Dec. 11, 2013
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities		$44,000,000
Loss Contingency, Range of Possible Loss, Maximum		32,000,000
Commitments for construction and acquisition of property, plant and equipment		689,000,000
Louisiana Department Of Environmental Quality [Member]
Loss Contingencies [Line Items]
Penalty Assessment			194,306
Former Operations
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities		25,000,000
Natural gas underground storage facilities
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities		8,000,000
Environmental Protection Agency [Member]
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities		11,000,000
Geismar Incident [Member]
Loss Contingencies [Line Items]
Notice of Penalty				99,000
Litigation Settlement, Amount	$36,000

Segment_Disclosures_Geographic

Segment Disclosures Geographic Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues from external customers:
Revenues from external customers	$7,637	$6,860	$7,486
Long-lived assets:
Long-lived assets	39,654	20,500	17,820
United States [Member]
Revenues from external customers:
Revenues from external customers	7,229	6,703	7,335
Long-lived assets:
Long-lived assets	38,290	19,260	16,940
Canada [Member]
Revenues from external customers:
Revenues from external customers	408	157	151
Long-lived assets:
Long-lived assets	$1,364	$1,240	$880

Segment_Disclosures_Recon_from

Segment Disclosures Recon from Segment to Consolidated (Details 1) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment revenues:
Total revenues	$7,637		$6,860		$7,486
Segment profit (loss)	4,435		1,701		1,960
Gain on remeasurement of equity-method investment	2,544	[1]	0	[1]	0	[1]
Equity earnings (losses)	144	[1]	134	[1]	111	[1]
Income (loss) from investments	0	[1]	28	[1]	49	[1]
Operating income (loss)	1,569		1,375		1,612
Other financial information:
Additions to long-lived assets	20,756		3,731		6,018
Depreciation and amortization	1,176		815		756
Total assets and equity method investments by reporting segment
Total assets	50,563		27,142
Equity Method Investments	8,400		4,360
Service [Member]
Segment revenues:
Total revenues	4,116		2,939		2,729
Product [Member]
Segment revenues:
Total revenues	3,521		3,921		4,757
Williams Partners [Member] | Service [Member]
Segment revenues:
Total revenues	3,106		2,914		2,714
Williams Partners [Member] | Product [Member]
Segment revenues:
Total revenues	3,521		3,921		4,757
Access Midstream [Member] | Service [Member]
Segment revenues:
Total revenues	781		0		0
Access Midstream [Member] | Product [Member]
Segment revenues:
Total revenues	0		0		0
Williams NGL & Petchem Services [Member] | Service [Member]
Segment revenues:
Total revenues	0		0		0
Williams NGL & Petchem Services [Member] | Product [Member]
Segment revenues:
Total revenues	0		0		0
Other [Member] | Service [Member]
Segment revenues:
Total revenues	229		25		15
Other [Member] | Product [Member]
Segment revenues:
Total revenues	0		0		0
Operating Segments [Member]
Segment revenues:
Operating income (loss)	1,747		1,539		1,800
Operating Segments [Member] | Williams Partners [Member]
Segment revenues:
Total revenues	6,628		6,835		7,471
Segment profit (loss)	1,743		1,677		1,907
Gain on remeasurement of equity-method investment	0
Equity earnings (losses)	132		104		111
Income (loss) from investments	0		-3		-4
Operating income (loss)	1,611		1,576		1,800
Other financial information:
Additions to long-lived assets	3,449		3,409		5,851
Depreciation and amortization	855		791		734
Total assets and equity method investments by reporting segment
Total assets	26,298		23,571
Equity Method Investments	2,395		2,187
Operating Segments [Member] | Williams Partners [Member] | Service [Member]
Segment revenues:
Total revenues	3,107		2,914		2,714
Operating Segments [Member] | Williams Partners [Member] | Product [Member]
Segment revenues:
Total revenues	3,521		3,921		4,757
Operating Segments [Member] | Access Midstream [Member]
Segment revenues:
Total revenues	781		0		0
Segment profit (loss)	2,803		61		0
Gain on remeasurement of equity-method investment	2,544
Equity earnings (losses)	90		30		0
Income (loss) from investments	1		31		0
Operating income (loss)	168		0		0
Other financial information:
Additions to long-lived assets	16,964		0		0
Depreciation and amortization	296		0		0
Total assets and equity method investments by reporting segment
Total assets	23,024		2,161
Equity Method Investments	6,004		2,161
Operating Segments [Member] | Access Midstream [Member] | Service [Member]
Segment revenues:
Total revenues	781		0		0
Operating Segments [Member] | Access Midstream [Member] | Product [Member]
Segment revenues:
Total revenues	0		0		0
Operating Segments [Member] | Williams NGL & Petchem Services [Member]
Segment revenues:
Total revenues	0		0		0
Segment profit (loss)	-115		-32		-3
Gain on remeasurement of equity-method investment	0
Equity earnings (losses)	-78		0		0
Income (loss) from investments	-1		0		0
Operating income (loss)	-36		-32		-3
Other financial information:
Additions to long-lived assets	291		295		136
Depreciation and amortization	0		0		0
Total assets and equity method investments by reporting segment
Total assets	612		486
Equity Method Investments	0		12
Operating Segments [Member] | Williams NGL & Petchem Services [Member] | Service [Member]
Segment revenues:
Total revenues	0		0		0
Operating Segments [Member] | Williams NGL & Petchem Services [Member] | Product [Member]
Segment revenues:
Total revenues	0		0		0
Operating Segments [Member] | Other [Member]
Segment revenues:
Total revenues	259		36		27
Segment profit (loss)	4		-5		56
Gain on remeasurement of equity-method investment	0
Equity earnings (losses)	0		0		0
Income (loss) from investments	0		0		53
Operating income (loss)	4		-5		3
Other financial information:
Additions to long-lived assets	54		27		31
Depreciation and amortization	25		24		22
Total assets and equity method investments by reporting segment
Total assets	1,220		1,359
Equity Method Investments	1		0
Operating Segments [Member] | Other [Member] | Service [Member]
Segment revenues:
Total revenues	259		36		27
Operating Segments [Member] | Other [Member] | Product [Member]
Segment revenues:
Total revenues	0		0		0
Intersegment Elimination [Member]
Segment revenues:
Total revenues	-31		-11		-12
Other financial information:
Additions to long-lived assets	-2
Total assets and equity method investments by reporting segment
Total assets	-591		-435
Equity Method Investments	0		0
Intersegment Elimination [Member] | Service [Member]
Segment revenues:
Total revenues	-31		-11		-12
Intersegment Elimination [Member] | Product [Member]
Segment revenues:
Total revenues	0		0		0
Intersegment Elimination [Member] | Williams Partners [Member] | Service [Member]
Segment revenues:
Total revenues	-1		0		0
Intersegment Elimination [Member] | Williams Partners [Member] | Product [Member]
Segment revenues:
Total revenues	0		0		0
Intersegment Elimination [Member] | Access Midstream [Member] | Service [Member]
Segment revenues:
Total revenues	0		0		0
Intersegment Elimination [Member] | Access Midstream [Member] | Product [Member]
Segment revenues:
Total revenues	0		0		0
Intersegment Elimination [Member] | Williams NGL & Petchem Services [Member] | Service [Member]
Segment revenues:
Total revenues	0		0		0
Intersegment Elimination [Member] | Williams NGL & Petchem Services [Member] | Product [Member]
Segment revenues:
Total revenues	0		0		0
Intersegment Elimination [Member] | Other [Member] | Service [Member]
Segment revenues:
Total revenues	-30		-11		-12
Intersegment Elimination [Member] | Other [Member] | Product [Member]
Segment revenues:
Total revenues	0		0		0
General Corporate Expenses [Member]
Segment revenues:
Operating income (loss)	($178)		($164)		($188)
[1]	Items also included in Segment profit (loss). (See Note 19 b Segment Disclosures.)

Schedule_I_Condensed_Financial2

Schedule I Condensed Financial Information Of Parent Company Only (Details) (USD $)	0 Months Ended	12 Months Ended
Share data in Thousands, except Per Share data, unless otherwise specified	Jun. 23, 2014	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Condensed Statement Of Comprehensive Income Parent Company Only [Abstract]
Equity earnings (losses)		$144,000,000	[1]	$134,000,000	[1]	$111,000,000	[1]
Interest incurred - external		-888,000,000		-611,000,000		-568,000,000
Gain on remeasurement of equity-method investment		2,544,000,000	[1]	0	[1]	0	[1]
Net insurance recoveries - Geismar Incident		232,000,000		40,000,000		0
Other income (expense) - net		31,000,000		0		-2,000,000
Income (loss) from continuing operations before income taxes		3,584,000,000		1,080,000,000		1,289,000,000
Provision for income taxes		1,249,000,000		401,000,000		360,000,000
Income (loss) from continuing operations		2,110,000,000		441,000,000		723,000,000
Income (loss) from discontinued operations		4,000,000		-11,000,000		136,000,000
Net income (loss) attributable to The Williams Companies, Inc.		2,114,000,000		430,000,000		859,000,000
Basic earnings (loss) per common share:
Income (loss) from continuing operations		$2.93		$0.65		$1.17
Income (loss) from discontinued operations		$0.01		($0.02)		$0.22
Net income (loss)		$2.94		$0.63		$1.39
Weighted-average shares (thousands)		719,325		682,948		619,792
Diluted earnings (loss) per common share:
Income (loss) from continuing operations		$2.91		$0.64		$1.15
Income (loss) from discontinued operations		$0.01		($0.02)		$0.22
Net income (loss)		$2.92		$0.62		$1.37
Weighted-average shares (thousands)		723,641		687,185		625,486
Other comprehensive income (loss):
Other comprehensive income (loss)		-176,000,000		198,000,000		27,000,000
Comprehensive Income (loss) attributable to The Williams Companies, Inc.		1,957,000,000		628,000,000		886,000,000
Assets, Current [Abstract]
Cash and cash equivalents		240,000,000		681,000,000		839,000,000
Other current assets and deferred charges		213,000,000		107,000,000
Total current assets		1,890,000,000		1,683,000,000
Property, plant, and equipment - net		28,081,000,000		18,210,000,000
Other noncurrent assets		619,000,000		599,000,000
Total assets		50,563,000,000		27,142,000,000
Liabilities, Current [Abstract]
Accounts payable		865,000,000		960,000,000
Long-term debt due within one year		4,000,000		1,000,000
Total current liabilities		2,567,000,000		1,983,000,000
Long-term debt		20,888,000,000		11,353,000,000
Deferred income taxes		4,712,000,000		3,529,000,000
Contingent liabilities and commitments
Equity: [Abstract]
Common stock		782,000,000		718,000,000
Total stockholders' equity		8,777,000,000		4,864,000,000
Total liabilities and stockholders' equity		50,563,000,000		27,142,000,000
Condensed Statement Of Cash Flows Parent Company Only [Abstract]
Net Cash Provided by (Used in) Operating Activities		2,115,000,000		2,217,000,000		1,835,000,000
FINANCING ACTIVITIES:
Proceeds from long-term debt		7,321,000,000		2,699,000,000		3,486,000,000
Payments of long-term debt		-1,828,000,000		-2,081,000,000		-1,468,000,000
Proceeds from issuance of common stock	3,378,000,000	3,416,000,000		18,000,000		2,550,000,000
Dividends paid		-1,412,000,000		-982,000,000		-742,000,000
Other - net		17,000,000		17,000,000		42,000,000
Net cash provided (used) by financing activities		7,601,000,000		1,677,000,000		5,036,000,000
INVESTING ACTIVITIES:
Capital expenditures		-20,756,000,000		-3,731,000,000		-6,018,000,000
Other - net		314,000,000		-19,000,000		108,000,000
Net cash provided (used) by investing activities		-10,157,000,000		-4,052,000,000		-6,921,000,000
Increase (decrease) in cash and cash equivalents		-441,000,000		-158,000,000		-50,000,000
Cash and cash equivalents at beginning of year		681,000,000		839,000,000		889,000,000
Cash and cash equivalents at end of year		240,000,000		681,000,000		839,000,000
Parent Company [Member]
Condensed Statement Of Comprehensive Income Parent Company Only [Abstract]
Equity in earnings of consolidated subsidiaries		1,799,000,000		1,564,000,000		1,895,000,000
Equity earnings (losses)		-7,000,000		30,000,000		0
Interest incurred - external		-206,000,000		-156,000,000		-128,000,000
Interest incurred - affiliate		-797,000,000		-722,000,000		-816,000,000
Interest income - affiliate		10,000,000		71,000,000		84,000,000
Gain on remeasurement of equity-method investment		2,544,000,000		0		0
Other income (expense) - net		-13,000,000		32,000,000		3,000,000
Income (loss) from continuing operations before income taxes		3,330,000,000		819,000,000		1,038,000,000
Provision for income taxes		1,220,000,000		378,000,000		315,000,000
Income (loss) from continuing operations		2,110,000,000		441,000,000		723,000,000
Income (loss) from discontinued operations		4,000,000		-11,000,000		136,000,000
Net income (loss) attributable to The Williams Companies, Inc.		2,114,000,000		430,000,000		859,000,000
Basic earnings (loss) per common share:
Income (loss) from continuing operations		$2.93		$0.65		$1.17
Income (loss) from discontinued operations		$0.01		($0.02)		$0.22
Net income (loss)		$2.94		$0.63		$1.39
Weighted-average shares (thousands)		719,325		682,948		619,792
Diluted earnings (loss) per common share:
Income (loss) from continuing operations		$2.91		$0.64		$1.15
Income (loss) from discontinued operations		$0.01		($0.02)		$0.22
Net income (loss)		$2.92		$0.62		$1.37
Weighted-average shares (thousands)		723,641		687,185		625,486
Other comprehensive income (loss):
Equity in other comprehensive income (loss) of consolidated subsidiaries		-96,000,000		-41,000,000		21,000,000
Other comprehensive income (loss) attributable to The Williams Companies, Inc.		-80,000,000		239,000,000		6,000,000
Other comprehensive income (loss)		-176,000,000		198,000,000		27,000,000
Other comprehensive income (loss) attributable to noncontrolling interests		-19,000,000		0		0
Comprehensive Income (loss) attributable to The Williams Companies, Inc.		1,957,000,000		628,000,000		886,000,000
Assets, Current [Abstract]
Cash and cash equivalents		49,000,000		282,000,000		340,000,000
Other current assets and deferred charges		246,000,000		167,000,000
Total current assets		295,000,000		449,000,000
Investments in and advances to consolidated subsidiaries		31,405,000,000		19,162,000,000
Investment in Access Midstream Partners		0		2,161,000,000
Property, plant, and equipment - net		99,000,000		68,000,000
Other noncurrent assets		46,000,000		34,000,000
Total assets		31,845,000,000		21,874,000,000
Liabilities, Current [Abstract]
Accounts payable		27,000,000		26,000,000
Long-term debt due within one year		0		1,000,000
Other current liabilities		174,000,000		147,000,000
Total current liabilities		201,000,000		174,000,000
Long-term debt		4,562,000,000		2,296,000,000
Notes payable - affiliates		13,295,000,000		10,830,000,000
Pension, other postretirement and other noncurrent liabilities		409,000,000		282,000,000
Deferred income taxes		4,601,000,000		3,428,000,000
Contingent liabilities and commitments
Equity: [Abstract]
Common stock		782,000,000		718,000,000
Other stockholders' equity		7,995,000,000		4,146,000,000
Total stockholders' equity		8,777,000,000		4,864,000,000
Total liabilities and stockholders' equity		31,845,000,000		21,874,000,000
Condensed Statement Of Cash Flows Parent Company Only [Abstract]
Net Cash Provided by (Used in) Operating Activities		-500,000,000		19,000,000		-11,000,000
FINANCING ACTIVITIES:
Proceeds from long-term debt		2,935,000,000		0		848,000,000
Payments of long-term debt		-671,000,000		-1,000,000		-28,000,000
Changes in notes payable to affiliates		2,465,000,000		1,892,000,000		520,000,000
Tax benefit of stock-based awards		25,000,000		19,000,000		44,000,000
Proceeds from issuance of common stock		3,416,000,000		18,000,000		2,550,000,000
Dividends paid		-1,412,000,000		-982,000,000		-742,000,000
Other - net		-17,000,000		-3,000,000		-7,000,000
Net cash provided (used) by financing activities		6,741,000,000		943,000,000		3,185,000,000
INVESTING ACTIVITIES:
Capital expenditures		-54,000,000		-23,000,000		-18,000,000
Payments to Acquire Businesses, Gross		-5,995,000,000		0		0
Purchase of investment in Access Midstream Partners		0		-4,000,000		-2,179,000,000
Changes in investments in and advances to consolidated subsidiaries		-450,000,000		-985,000,000		-953,000,000
Other - net		25,000,000		-8,000,000		24,000,000
Net cash provided (used) by investing activities		-6,474,000,000		-1,020,000,000		-3,126,000,000
Increase (decrease) in cash and cash equivalents		-233,000,000		-58,000,000		48,000,000
Cash and cash equivalents at beginning of year		282,000,000		340,000,000		292,000,000
Cash and cash equivalents at end of year		49,000,000		282,000,000		340,000,000
Guarantees [Abstract]
Guarantor Obligations, Maximum Exposure, Undiscounted		681,000,000
Cash Dividends Received [Abstract]
Proceeds from Dividends Received		$1,900,000,000		$1,500,000,000		$1,100,000,000
[1]	Items also included in Segment profit (loss). (See Note 19 b Segment Disclosures.)

Schedule_II_Valuation_and_Qual1

Schedule II Valuation and Qualifying Accounts (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Allowance for doubtful accounts and for notes receivable [Member]
Valuation And Qualifying Accounts
Beginning Balance	$0	[1]	$0	[1]	$1	[1]
Additions Charged (Credited) To Cost and Expenses	0		0		0
Additions Other	0		0		0
Deductions	0		0		1	[2]
Ending Balance	0	[1]	0	[1]	0	[1]
Deferred Tax Asset Valuation Allowance [Member]
Valuation And Qualifying Accounts
Beginning Balance	181	[1]	144	[1]	145	[1]
Additions Charged (Credited) To Cost and Expenses	25		37		-1
Additions Other	0		0		0
Deductions	0		0		0
Ending Balance	$206	[1]	$181	[1]	$144	[1]
[1]	Deducted from related assets.
[2]	(2) Represents balances written off, reclassifications, and recoveries.