Earnings (Loss) Per Common Share from Continuing Operations (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Earnings (loss) per common share from continuing operations
Income (loss) from continuing operations attributable to The Williams Companies, Inc. available to common stockholders for basic and diluted earnings (loss) per common share	$ 723	$ 803	$ 104
Basic weighted-average shares	619,792,000	588,553,000	584,552,000
Diluted weighted-average shares	625,486,000	598,175,000	590,699,000
Earnings (loss) per common share from continuing operations:
Basic	$ 1.17	$ 1.36	$ 0.17
Diluted	$ 1.15	$ 1.34	$ 0.17
Stock options excluded
Quarter Weighted Average Market Price	$ 33.38	$ 24.51	$ 22.47
Nonvested restricted stock units [Member]
Effect of dilutive securities:
Incremental common shares attributable to share-based payment arrangements under effects of dilutive securities item	2,694,000	4,332,000	3,190,000
Stock options [Member]
Effect of dilutive securities:
Incremental common shares attributable to share-based payment arrangements under effects of dilutive securities item	2,608,000	3,374,000	2,957,000
Convertible debentures [Member]
Effect of dilutive securities:
Incremental dilutive shares, Convertible debt	392,000	1,916,000	0
Earnings (loss) per common share from continuing operations (Textuals) [Abstract]
Interest Expenses, net of tax		0.7
Number of weighted-average shares excluded from computation of diluted earnings per common share			2,200,000
Threshold of income from continuing operations attributable to company available to common stockholders that would cause the convertible debentures to become dilutive.			$ 222
Out of the money options [Member]
Stock options excluded
Weighted-average exercise price of options excluded	$ 0	$ 29.68	$ 32.41
Exercise price ranges of options excluded, minimum	$ 0.00	$ 26.10	$ 22.68
Exercise price ranges of options excluded, maximum	$ 0.00	$ 29.72	$ 40.51
Earnings (loss) per common share from continuing operations (Textuals) [Abstract]
Number of weighted-average shares excluded from computation of diluted earnings per common share	0	900,000	2,400,000