Schedule I Condensed Financial Information Of Parent Only (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	1 Months Ended		12 Months Ended
	Dec. 31, 2012	Apr. 30, 2012	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Condensed Statement Of Comprehensive Income Parent Company Only [Abstract]
Interest incurred - external			$ (568,000,000)	$ (598,000,000)	$ (628,000,000)
Early debt retirement costs			0	(271,000,000)	(606,000,000)
Other income (expense) - net			(2,000,000)	11,000,000	(12,000,000)
Income from continuing operations before income taxes			1,289,000,000	1,202,000,000	385,000,000
Provision for income taxes			360,000,000	124,000,000	114,000,000
Income (loss) from continuing operations			723,000,000	803,000,000	104,000,000
Income (loss) from discontinued operations			136,000,000	(427,000,000)	(1,201,000,000)
Net income (loss)			859,000,000	376,000,000	(1,097,000,000)
Basic earnings (loss) per common share:
Income (loss) from continuing operations			$ 1.17	$ 1.36	$ 0.17
Income (loss) from discontinued operations			$ 0.22	$ (0.72)	$ (2.05)
Net income (loss)			$ 1.39	$ 0.64	$ (1.88)
Weighted-average shares (thousands)			619,792	588,553	584,552
Diluted earnings (loss) per common share:
Income (loss) from continuing operations			$ 1.15	$ 1.34	$ 0.17
Income (loss) from discontinued operations			$ 0.22	$ (0.71)	$ (2.03)
Net income (loss)			$ 1.37	$ 0.63	$ (1.86)
Weighted-average shares (thousands)			625,486	598,175	590,699
Other comprehensive income (loss):
Other comprehensive income (loss)			27,000,000	(88,000,000)	86,000,000
Comprehensive Income (loss) attributable to The Williams Companies, Inc.			886,000,000	288,000,000	(1,011,000,000)
Assets, Current [Abstract]
Cash and cash equivalents	839,000,000		839,000,000	889,000,000
Other current assets	66,000,000		66,000,000	107,000,000
Total current assets	1,924,000,000		1,924,000,000	1,894,000,000
Property, plant and equipment - net	15,467,000,000		15,467,000,000	12,580,000,000
Other noncurrent assets	596,000,000		596,000,000	593,000,000
Total assets	24,327,000,000		24,327,000,000	16,502,000,000
Liabilities, Current [Abstract]
Long-term debt due within one year	1,000,000		1,000,000	353,000,000
Total current liabilities	1,549,000,000		1,549,000,000	1,675,000,000
Long-term debt	10,735,000,000		10,735,000,000	8,369,000,000
Deferred income taxes	2,841,000,000		2,841,000,000	2,157,000,000
Contingent liabilities and commitments
Equity: [Abstract]
Common stock	716,000,000		716,000,000	626,000,000
Total stockholders' equity	7,427,000,000		7,427,000,000	2,586,000,000	8,134,000,000	8,562,000,000
Total liabilities and stockholders' equity	24,327,000,000		24,327,000,000	16,502,000,000
Condensed Statement Of Cash Flows Parent Company Only [Abstract]
Net Cash Provided by (Used in) Operating Activities			1,835,000,000	3,439,000,000	2,651,000,000
FINANCING ACTIVITIES:
Proceeds from long-term debt			3,486,000,000	3,172,000,000	5,129,000,000
Payments of long-term debt			(1,468,000,000)	(2,055,000,000)	(4,305,000,000)
Premiums paid on early debt retirements			0	(254,000,000)	(574,000,000)
Proceeds from issuance of common stock	1,600,000,000	887,000,000	2,550,000,000	49,000,000	12,000,000
Dividends paid			(742,000,000)	(457,000,000)	(284,000,000)
Other - net			55,000,000	(7,000,000)	5,000,000
Net cash provided (used) by financing activities			5,036,000,000	(342,000,000)	573,000,000
INVESTING ACTIVITIES:
Capital expenditures			(2,529,000,000)	(2,796,000,000)	(2,788,000,000)
Other - net			108,000,000	29,000,000	33,000,000
Net cash provided (used) by investing activities			(6,921,000,000)	(3,003,000,000)	(4,296,000,000)
Increase (decrease) in cash and cash equivalents			(50,000,000)	94,000,000	(1,072,000,000)
Cash and cash equivalents at beginning of year			889,000,000
Cash and cash equivalents at end of year	839,000,000		839,000,000	889,000,000
Parent Company [Member]
Condensed Statement Of Comprehensive Income Parent Company Only [Abstract]
Equity in earnings of consolidated subsidiaries			1,895,000,000	1,962,000,000	1,457,000,000
Interest incurred - external			(128,000,000)	(186,000,000)	(235,000,000)
Interest incurred - affiliate			(816,000,000)	(622,000,000)	(460,000,000)
Interest income - affiliate			84,000,000	84,000,000	76,000,000
Early debt retirement costs			0	(271,000,000)	(606,000,000)
Other income (expense) - net			3,000,000	(45,000,000)	(41,000,000)
Income from continuing operations before income taxes			1,038,000,000	922,000,000	191,000,000
Provision for income taxes			315,000,000	119,000,000	87,000,000
Income (loss) from continuing operations			723,000,000	803,000,000	104,000,000
Income (loss) from discontinued operations			136,000,000	(427,000,000)	(1,201,000,000)
Net income (loss)			859,000,000	376,000,000	(1,097,000,000)
Basic earnings (loss) per common share:
Income (loss) from continuing operations			$ 1.17	$ 1.36	$ 0.17
Income (loss) from discontinued operations			$ 0.22	$ (0.72)	$ (2.05)
Net income (loss)			$ 1.39	$ 0.64	$ (1.88)
Weighted-average shares (thousands)			619,792	588,553	584,552
Diluted earnings (loss) per common share:
Income (loss) from continuing operations			$ 1.15	$ 1.34	$ 0.17
Income (loss) from discontinued operations			$ 0.22	$ (0.71)	$ (2.03)
Net income (loss)			$ 1.37	$ 0.63	$ (1.86)
Weighted-average shares (thousands)			625,486	598,175	590,699
Other comprehensive income (loss):
Equity in other comprehensive income (loss) of consolidated subsidiaries			21,000,000	35,000,000	121,000,000
Other comprehensive income (loss) attributable to The Williams Companies, Inc.			6,000,000	(123,000,000)	(35,000,000)
Other comprehensive income (loss)			27,000,000	(88,000,000)	86,000,000
Comprehensive Income (loss) attributable to The Williams Companies, Inc.			886,000,000	288,000,000	(1,011,000,000)
Assets, Current [Abstract]
Cash and cash equivalents	340,000,000		340,000,000	292,000,000	102,000,000
Other current assets	229,000,000		229,000,000	128,000,000
Total current assets	569,000,000		569,000,000	420,000,000
Investments in and advances to consolidated subsidiaries	16,686,000,000		16,686,000,000	13,602,000,000
Investment in Access Midstream Partners	2,187,000,000		2,187,000,000	0
Property, plant and equipment - net	62,000,000		62,000,000	61,000,000
Other noncurrent assets	117,000,000		117,000,000	142,000,000
Total assets	19,621,000,000		19,621,000,000	14,225,000,000
Liabilities, Current [Abstract]
Accounts payable and accrued liabilities	29,000,000		29,000,000	143,000,000
Long-term debt due within one year	1,000,000		1,000,000	28,000,000
Other current liabilities	122,000,000		122,000,000	58,000,000
Total current liabilities	152,000,000		152,000,000	229,000,000
Long-term debt	2,298,000,000		2,298,000,000	1,456,000,000
Notes payable affiliates	8,938,000,000		8,938,000,000	8,418,000,000
Pension, other postretirement and other liabilities	712,000,000		712,000,000	732,000,000
Deferred income taxes	2,769,000,000		2,769,000,000	2,094,000,000
Contingent liabilities and commitments
Equity: [Abstract]
Common stock	716,000,000		716,000,000	626,000,000
Other stockholders' equity	4,036,000,000		4,036,000,000	670,000,000
Total stockholders' equity	4,752,000,000		4,752,000,000	1,296,000,000
Total liabilities and stockholders' equity	19,621,000,000		19,621,000,000	14,225,000,000
Condensed Statement Of Cash Flows Parent Company Only [Abstract]
Net Cash Provided by (Used in) Operating Activities			(11,000,000)	(286,000,000)	3,371,000,000
FINANCING ACTIVITIES:
Proceeds from long-term debt			848,000,000	75,000,000	100,000,000
Payments of long-term debt			(28,000,000)	(871,000,000)	(3,102,000,000)
Changes in notes payable to affiliates			520,000,000	(590,000,000)	1,422,000,000
Tax benefit of stock-based awards			44,000,000	22,000,000	7,000,000
Premiums paid on early debt retirements			0	(254,000,000)	(574,000,000)
Proceeds from issuance of common stock			2,550,000,000	49,000,000	12,000,000
Dividends paid			(742,000,000)	(457,000,000)	(284,000,000)
Other - net			(7,000,000)	(5,000,000)	(12,000,000)
Net cash provided (used) by financing activities			3,185,000,000	(2,031,000,000)	(2,431,000,000)
INVESTING ACTIVITIES:
Capital expenditures			(18,000,000)	(28,000,000)	(15,000,000)
Purchase of investment in Access Midstream Partners			2,179,000,000	0	0
Changes in investments in and advances to consolidated subsidiaries			(953,000,000)	2,553,000,000	(2,054,000,000)
Other - net			24,000,000	(18,000,000)	0
Net cash provided (used) by investing activities			(3,126,000,000)	2,507,000,000	(2,069,000,000)
Increase (decrease) in cash and cash equivalents			48,000,000	190,000,000	(1,129,000,000)
Cash and cash equivalents at beginning of year			292,000,000	102,000,000	1,231,000,000
Cash and cash equivalents at end of year	340,000,000		340,000,000	292,000,000	102,000,000
Guarantees [Abstract]
Guarantor Obligations, Maximum Exposure, Undiscounted	1,500,000,000		1,500,000,000
Cash Dividends Received [Abstract]
Proceeds from Dividends Received			$ 1,100,000,000	$ 1,200,000,000	$ 5,000,000,000