Earnings (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share Table [Line Items]
Net income (loss) attributable to The Williams Companies, Inc. available to common stockholders for basic and diluted earnings (loss) per common share	$ 81	$ (405)	$ 454	$ (470)
Basic weighted-average shares	826,426	750,649	825,492	750,491
Effect of dilutive securities:
Diluted weighted-average shares	828,575	750,649	827,531	750,491
Earnings (loss) per common share:
Basic	$ 0.10	$ (0.54)	$ 0.55	$ (0.63)
Diluted	$ 0.10	$ (0.54)	$ 0.55	$ (0.63)
Nonvested restricted stock units [Member]
Effect of dilutive securities:
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	1,499	0	1,402	0
Stock Options [Member]
Effect of dilutive securities:
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	650	0	637	0