Revenue Recognition Impact of Adoption of ASC 606 (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Service revenues	$ 8,604
Sales revenue services commodity consideration	400	$ 0	$ 0
Total revenues	8,686	8,031	7,499
Processing commodity expenses	137	0	0
Operating and maintenance expenses	1,507	1,576	1,592
Depreciation and amortization	1,725	1,736	1,763
Other Asset Impairment Charges	1,915	1,248	873
Costs and Expenses	7,918	7,104	6,810
Operating Income (Loss)	768	927	689
Income (Loss) from Equity Method Investments	396	434	397
Other investing income (loss) – net	219	282	63
Interest incurred	(1,160)	(1,116)	(1,217)
Interest capitalized	48	33	38
Income (loss) before income taxes	331	535	(375)
Provision (benefit) for income taxes	138	(1,974)	(25)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	193	2,509	(350)
Net Income (Loss) Attributable to Noncontrolling Interest	348	335	74
Net income (loss) attributable to The Williams Companies, Inc.	$ (155)	$ 2,174	$ (424)
Net income (loss)	$ (0.16)	$ 2.63	$ (0.57)
Net income (loss)	$ (0.16)	$ 2.62	$ (0.57)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 223	$ 2,609	$ (178)
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	346	334	143
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(123)	2,275	(321)
Inventory, Net	130	113
Other current assets and deferred charges	174	191
Assets, Current	1,464	2,179
Investments	7,821	6,552
Property, Plant and Equipment, Net	27,504	28,211
Intangible assets – net of accumulated amortization	7,767	8,791
Other Assets, Noncurrent	746	619
Total assets	45,302	46,352
Accrued Liabilities, Current	1,102	1,167
Liabilities, Current	1,811	2,646
Deferred income tax liabilities	1,524	3,147
Other Liabilities and Deferred Revenue, Noncurrent	3,603	3,950
Retained Earnings (Accumulated Deficit)	(10,002)	(8,434)
Stockholders' Equity Attributable to Parent	14,660	9,656
Stockholders' Equity Attributable to Noncontrolling Interest	1,337	6,519
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	15,997	16,175	14,046	$ 16,225
Total liabilities and equity	45,302	46,352
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(121)	37
Noncontrolling Interest, Decrease from Deconsolidation	(267)
Stockholders' Equity, Period Increase (Decrease)	(178)	2,129	(2,179)
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]
Sales revenue services commodity consideration	(400)
Total revenues	(176)
Processing commodity expenses	(137)
Operating and maintenance expenses	1
Depreciation and amortization	2
Other Asset Impairment Charges	202
Costs and Expenses	(56)
Operating Income (Loss)	(120)
Income (Loss) from Equity Method Investments	1
Other investing income (loss) – net	84
Interest incurred	16
Interest capitalized	(10)
Income (loss) before income taxes	(29)
Provision (benefit) for income taxes	(9)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(20)
Net Income (Loss) Attributable to Noncontrolling Interest	(1)
Net income (loss) attributable to The Williams Companies, Inc.	$ (19)
Net income (loss)	$ (0.02)
Net income (loss)	$ (0.02)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ (20)
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	(1)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(19)
Inventory, Net	(13)
Assets, Current	(13)
Investments	1
Property, Plant and Equipment, Net	(212)
Intangible assets – net of accumulated amortization	61
Other Assets, Noncurrent	(4)
Total assets	(167)
Accrued Liabilities, Current	67
Liabilities, Current	67
Deferred income tax liabilities	20
Other Liabilities and Deferred Revenue, Noncurrent	(346)
Retained Earnings (Accumulated Deficit)	64
Stockholders' Equity Attributable to Parent	64
Stockholders' Equity Attributable to Noncontrolling Interest	28
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	92
Total liabilities and equity	(167)
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	121
Noncontrolling Interest, Decrease from Deconsolidation	(9)
Stockholders' Equity, Period Increase (Decrease)	92
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]
Sales revenue services commodity consideration	0
Total revenues	8,510
Processing commodity expenses	0
Operating and maintenance expenses	1,508
Depreciation and amortization	1,727
Other Asset Impairment Charges	2,117
Costs and Expenses	7,862
Operating Income (Loss)	648
Income (Loss) from Equity Method Investments	397
Other investing income (loss) – net	303
Interest incurred	(1,144)
Interest capitalized	38
Income (loss) before income taxes	302
Provision (benefit) for income taxes	129
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	173
Net Income (Loss) Attributable to Noncontrolling Interest	347
Net income (loss) attributable to The Williams Companies, Inc.	$ (174)
Net income (loss)	$ (0.18)
Net income (loss)	$ (0.18)
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 203
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	345
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(142)
Inventory, Net	117
Assets, Current	1,451
Investments	7,822
Property, Plant and Equipment, Net	27,292
Intangible assets – net of accumulated amortization	7,828
Other Assets, Noncurrent	742
Total assets	45,135
Accrued Liabilities, Current	1,169
Liabilities, Current	1,878
Deferred income tax liabilities	1,544
Other Liabilities and Deferred Revenue, Noncurrent	3,257
Retained Earnings (Accumulated Deficit)	(9,938)
Stockholders' Equity Attributable to Parent	14,724
Stockholders' Equity Attributable to Noncontrolling Interest	1,365
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	16,089
Total liabilities and equity	45,135
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	0
Noncontrolling Interest, Decrease from Deconsolidation	(276)
Stockholders' Equity, Period Increase (Decrease)	(86)
Service [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Service revenues	5,502	5,312	5,171
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]
Service revenues	89
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]
Service revenues	5,591
Product [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Service revenues	2,784	2,719	2,328
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]
Service revenues	135
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]
Service revenues	2,919
Oil and Gas, Purchased [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Product costs	2,707	$ 2,300	$ 1,725
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	(124)
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	$ 2,583