Earnings (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
Earnings (loss) per common share
Net income (loss) available to common stockholders	$ (156)		$ 2,174	$ (424)
Basic weighted-average shares	973,626		826,177	750,673
Effect of dilutive securities:
Diluted weighted-average shares	973,626	[1]	828,518	750,673	[1]
Earnings (loss) per common share:
Basic	$ (0.16)		$ 2.63	$ (0.57)
Diluted	$ (0.16)		$ 2.62	$ (0.57)
Nonvested restricted stock units [Member]
Effect of dilutive securities:
Incremental common shares attributable to share-based payment arrangements under effects of dilutive securities item	0		1,704	0
Earnings (loss) per common share from continuing operations (Textuals) [Abstract]
Number of weighted-average shares excluded from computation of diluted earnings per common share	2,000			600
Stock options [Member]
Effect of dilutive securities:
Incremental common shares attributable to share-based payment arrangements under effects of dilutive securities item	0		637	0
Earnings (loss) per common share from continuing operations (Textuals) [Abstract]
Number of weighted-average shares excluded from computation of diluted earnings per common share	500			500

[1] For the years ended December 31, 2018 and December 31, 2016, 2.0 million and 0.6 million weighted-average nonvested restricted stock units, respectively, and 0.5 million and 0.5 million weighted-average stock options, respectively, have been excluded from the computation of diluted earnings (loss) per common share as their inclusion would be antidilutive due to our loss attributable to The Williams Companies, Inc.