Consolidated Statement of Operations - USD ($) shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Revenues	$ 7,719	$ 8,201	$ 8,686
Costs and expenses:
Operating and maintenance expenses	1,326	1,468	1,507
Depreciation and amortization expenses	1,721	1,714	1,725
Selling, general, and administrative expenses	466	558	569
Impairment of certain assets (Note 18)	182	464	1,915
Impairment of goodwill (Note 18)	187	0	0
Gain on sale of certain assets and businesses (Note 3)	0	2	(692)
Other (income) expense – net	22	8	50
Total costs and expenses	5,517	6,280	7,918
Operating income (loss)	2,202	1,921	768
Equity earnings (losses) (Note 7)	328	375	396
Impairment of equity-method investments (Note 18)	(1,046)	(186)	(32)
Other investing income (loss) – net (Note 7)	8	107	219
Interest incurred	(1,192)	(1,218)	(1,160)
Interest capitalized	20	32	48
Other income (expense) – net	(43)	33	92
Income (loss) from continuing operations before income taxes	277	1,064	331
Less: Provision (benefit) for income taxes	79	335	138
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	198	729	193
Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	0	(15)	0
Net income (loss)	198	714	193
Less: Net income (loss) attributable to noncontrolling interests	(13)	(136)	348
Amounts attributable to The Williams Companies, Inc. available to common stockholders:
Net income (loss) attributable to The Williams Companies, Inc.	211	850	(155)
Less: Preferred stock dividends (Note 16)	3	3	1
Net income (loss) available to common stockholders	208	847	(156)
Income (loss) from continuing operations available to common stockholders	$ 208	$ 862	$ (156)
Basic earnings (loss) per common share:
Net income (loss)	$ 0.17	$ 0.70	$ (0.16)
Basic	0.17	0.71	(0.16)
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	$ 0	$ (0.01)	$ 0
Weighted-average shares (thousands)	1,213,631	1,212,037	973,626
Diluted earnings (loss) per common share:
Net income (loss)	$ 0.17	$ 0.70	$ (0.16)
Diluted	0.17	0.71	(0.16)
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	$ 0	$ (0.01)	$ 0
Weighted-average shares (thousands)	1,215,165	1,214,011	973,626	[1]
Service [Member]
Revenues:
Revenues	$ 5,924	$ 5,933	$ 5,502
NonRegulated Service Commodity Consideration [Member]
Revenues:
Revenues	129	203	400
Product [Member]
Revenues:
Revenues	1,666	2,065	2,784
Oil and Gas, Purchased [Member]
Costs and expenses:
Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization	1,545	1,961	2,707
Natural Gas Purchased For Shrink [Member]
Costs and expenses:
Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization	$ 68	$ 105	$ 137

[1] For the year ended December 31, 2018, 2.0 million weighted-average nonvested restricted stock units and 0.5 million weighted-average stock options have been excluded from the computation of diluted earnings (loss) per common share as their inclusion would be antidilutive due to our loss from continuing operations attributable to The Williams Companies, Inc.