Revenue Recognition Impact of Adoption of ASC 606 (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 2,280		$ 6,423
Service revenues – commodity consideration	121	$ 0	316	$ 0
Total revenues	2,303	1,891	6,482	5,803
Processing commodity expenses	30	0	91	0
Operating Costs and Expenses	389	403	1,134	1,166
Depreciation and amortization expenses	425	433	1,290	1,308
Total costs and expenses	1,802	1,617	5,080	4,721
Operating Income (Loss)	501	274	1,402	1,082
Equity earnings (losses)	105	115	279	347
Other investing income (loss) - net	2	4	74	278
Interest incurred	(286)	(275)	(856)	(842)
Interest capitalized	16	8	38	24
Income (loss) before income taxes	390	149	1,036	1,013
Provision (benefit) for income taxes	190	24	297	126
Net income (loss)	200	125	739	887
Less: Net income (loss) attributable to noncontrolling interests	71	92	323	400
Net income (loss) attributable to The Williams Companies Inc	$ 129	$ 33	$ 416	$ 487
Net income (loss)	$ 0.13	$ 0.04	$ 0.47	$ 0.59
Net income (loss)	$ 0.13	$ 0.04	$ 0.46	$ 0.59
Net income (loss)	$ 206	$ 122	$ 748	$ 893
Less: Comprehensive income (loss) attributable to noncontrolling interests	72	89	321	398
Comprehensive income (loss) attributable to The Williams Companies, Inc.	134	33	427	495
Inventories	153		153		$ 113
Other current assets and deferred charges	242		242		184
Total current assets	1,984		1,984		2,179
Investments	7,427		7,427		6,552
Property, plant, and equipment	39,953		39,953		39,513
Property, plant, and equipment – net	28,674		28,674		28,211
Intangible assets - net of accumulated amortization	8,324		8,324		8,791
Regulatory assets, deferred charges, and other	744		744		619
Total assets	47,153		47,153		46,352
Deferred income tax liabilities	1,648		1,648		3,147
Regulatory liabilities, deferred income, and other	4,376		4,376		3,950
Retained deficit	(9,018)		(9,018)		(8,434)
Total stockholders’ equity	15,610		15,610		9,656
Noncontrolling interests in consolidated subsidiaries	1,349		1,349		6,519
Total equity	16,959		16,959		16,175
Total liabilities and equity	47,153		47,153		$ 46,352
Adoption of ASC 606			(121)
Deconsolidation of subsidiary			(267)
Net increase (decrease) in equity			784
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Service revenues – commodity consideration	(121)		(316)
Total revenues	(72)		(214)
Processing commodity expenses	(30)		(91)
Operating Costs and Expenses			3
Depreciation and amortization expenses	1		2
Total costs and expenses	(77)		(229)
Operating Income (Loss)	5		15
Equity earnings (losses)			1
Other investing income (loss) - net			(9)
Interest incurred	4		11
Interest capitalized	(2)		(6)
Income (loss) before income taxes	7		12
Provision (benefit) for income taxes	1		1
Net income (loss)	6		11
Less: Net income (loss) attributable to noncontrolling interests	(1)
Net income (loss) attributable to The Williams Companies Inc	$ 7		$ 11
Net income (loss)	$ 0.01		$ 0.01
Net income (loss)	$ 0.01		$ 0.01
Net income (loss)	$ 6		$ 11
Less: Comprehensive income (loss) attributable to noncontrolling interests	(1)
Comprehensive income (loss) attributable to The Williams Companies, Inc.	7		11
Inventories	(8)		(8)
Other current assets and deferred charges	(53)		(53)
Total current assets	(61)		(61)
Investments	(1)		(1)
Property, plant, and equipment	(6)		(6)
Property, plant, and equipment – net	(6)		(6)
Intangible assets - net of accumulated amortization	63		63
Regulatory assets, deferred charges, and other	(4)		(4)
Total assets	(9)		(9)
Deferred income tax liabilities	27		27
Regulatory liabilities, deferred income, and other	(159)		(159)
Retained deficit	95		95
Total stockholders’ equity	95		95
Noncontrolling interests in consolidated subsidiaries	28		28
Total equity	123		123
Total liabilities and equity	(9)		(9)
Adoption of ASC 606			121
Deconsolidation of subsidiary			(9)
Net increase (decrease) in equity			123
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Service revenues – commodity consideration	0		0
Total revenues	2,231		6,268
Processing commodity expenses	0		0
Operating Costs and Expenses			1,137
Depreciation and amortization expenses	426		1,292
Total costs and expenses	1,725		4,851
Operating Income (Loss)	506		1,417
Equity earnings (losses)			280
Other investing income (loss) - net			65
Interest incurred	(282)		(845)
Interest capitalized	14		32
Income (loss) before income taxes	397		1,048
Provision (benefit) for income taxes	191		298
Net income (loss)	206		750
Less: Net income (loss) attributable to noncontrolling interests	70
Net income (loss) attributable to The Williams Companies Inc	$ 136		$ 427
Net income (loss)	$ 0.14		$ 0.48
Net income (loss)	$ 0.14		$ 0.47
Net income (loss)	$ 212		$ 759
Less: Comprehensive income (loss) attributable to noncontrolling interests	71
Comprehensive income (loss) attributable to The Williams Companies, Inc.	141		438
Inventories	145		145
Other current assets and deferred charges	189		189
Total current assets	1,923		1,923
Investments	7,426		7,426
Property, plant, and equipment	39,947		39,947
Property, plant, and equipment – net	28,668		28,668
Intangible assets - net of accumulated amortization	8,387		8,387
Regulatory assets, deferred charges, and other	740		740
Total assets	47,144		47,144
Deferred income tax liabilities	1,675		1,675
Regulatory liabilities, deferred income, and other	4,217		4,217
Retained deficit	(8,923)		(8,923)
Total stockholders’ equity	15,705		15,705
Noncontrolling interests in consolidated subsidiaries	1,377		1,377
Total equity	17,082		17,082
Total liabilities and equity	47,144		47,144
Adoption of ASC 606			0
Deconsolidation of subsidiary			(276)
Net increase (decrease) in equity			907
Service [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,371	1,310	4,062	3,853
Service [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	5		16
Service [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,376		4,078
Product [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	811	581	2,104	1,950
Product [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	44		86
Product [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	855		2,190
Oil and Gas, Purchased [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Product costs	790	$ 504	2,039	$ 1,620
Oil and Gas, Purchased [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Product costs	(48)		(143)
Oil and Gas, Purchased [Member] | Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Product costs	$ 742		$ 1,896