Revenue Recognition Impact of Adoption of ASC 606 (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Sales Revenue, Services, Net	$ 1,351	$ 1,261
Sales revenue services commodity consideration	101	0
Sales Revenue, Goods, Net	636	727
Total revenues	2,088	1,988
Cost of Purchased Oil and Gas	613	579
Processing commodity expenses	35	0
Operating Costs and Expenses	357	371
Depreciation and amortization expenses	431	442
Costs and Expenses	1,597	1,558
Operating Income (Loss)	491	430
Interest Costs Incurred	(282)	(287)
Interest Costs Capitalized Adjustment	9	7
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	325	606
Provision (benefit) for income taxes	55	37
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	270	569
Net Income (Loss) Attributable to Noncontrolling Interest	118	196
Net income (loss) attributable to The Williams Companies Inc	152	373
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	276	575
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	119	197
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	157	$ 378
Inventory, Net	160		$ 113
Other Assets, Current	204		191
Assets, Current	2,399		2,179
Property, plant, and equipment	40,467		39,513
Property, Plant and Equipment, Net	28,847		28,211
Equity Method Investments	6,513		6,552
Intangible assets - net of accumulated amortization	8,644		8,791
Other Assets, Noncurrent	649		619
Total assets	47,052		46,352
Deferred Tax Liabilities, Net, Noncurrent	3,196		3,147
Other Liabilities and Deferred Revenue, Noncurrent	4,410		3,950
Retained deficit	(8,587)		(8,434)
Stockholders' Equity Attributable to Parent	9,473		9,656
Stockholders' Equity Attributable to Noncontrolling Interest	6,430		6,519
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	15,903		16,175
Liabilities and Equity	47,052		$ 46,352
Adoption of ASC 606	(121)
Stockholders' Equity, Period Increase (Decrease)	(272)
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, Net	5
Sales revenue services commodity consideration	(101)
Sales Revenue, Goods, Net	10
Total revenues	(86)
Cost of Purchased Oil and Gas	(55)
Processing commodity expenses	(35)
Operating Costs and Expenses	(1)
Depreciation and amortization expenses	1
Costs and Expenses	(90)
Operating Income (Loss)	4
Interest Costs Incurred	3
Interest Costs Capitalized Adjustment	(2)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	5
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	5
Net Income (Loss) Attributable to Noncontrolling Interest	2
Net income (loss) attributable to The Williams Companies Inc	3
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	5
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	2
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	3
Inventory, Net	(8)
Other Assets, Current	(20)
Assets, Current	(28)
Property, plant, and equipment	(2)
Property, Plant and Equipment, Net	(2)
Equity Method Investments	(1)
Intangible assets - net of accumulated amortization	63
Other Assets, Noncurrent	(4)
Total assets	28
Deferred Tax Liabilities, Net, Noncurrent	27
Other Liabilities and Deferred Revenue, Noncurrent	(125)
Retained deficit	87
Stockholders' Equity Attributable to Parent	87
Stockholders' Equity Attributable to Noncontrolling Interest	39
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	126
Liabilities and Equity	28
Adoption of ASC 606	121
Stockholders' Equity, Period Increase (Decrease)	126
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, Net	1,356
Sales revenue services commodity consideration	0
Sales Revenue, Goods, Net	646
Total revenues	2,002
Cost of Purchased Oil and Gas	558
Processing commodity expenses	0
Operating Costs and Expenses	356
Depreciation and amortization expenses	432
Costs and Expenses	1,507
Operating Income (Loss)	495
Interest Costs Incurred	(279)
Interest Costs Capitalized Adjustment	7
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	330
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	275
Net Income (Loss) Attributable to Noncontrolling Interest	120
Net income (loss) attributable to The Williams Companies Inc	155
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	281
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	121
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	160
Inventory, Net	152
Other Assets, Current	184
Assets, Current	2,371
Property, plant, and equipment	40,465
Property, Plant and Equipment, Net	28,845
Equity Method Investments	6,512
Intangible assets - net of accumulated amortization	8,707
Other Assets, Noncurrent	645
Total assets	47,080
Deferred Tax Liabilities, Net, Noncurrent	3,223
Other Liabilities and Deferred Revenue, Noncurrent	4,285
Retained deficit	(8,500)
Stockholders' Equity Attributable to Parent	9,560
Stockholders' Equity Attributable to Noncontrolling Interest	6,469
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	16,029
Liabilities and Equity	47,080
Adoption of ASC 606	0
Stockholders' Equity, Period Increase (Decrease)	$ (146)