Basis of Presentation (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Schedule of Equity Method Investments [Line Items]
Contribution of equity earnings in Gulfstream	$ 45	$ 39	$ 85	$ 79
Overstatement of noncontrolling interests in consolidated subsidiaries				346
Understatement of capital in excess of par value				346
Noncontrolling Interests
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Change between ownership interest and noncontrolling interests resulting from the restructuring	(30)		(30)	454
Originally reported
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Change between ownership interest and noncontrolling interests resulting from the restructuring				800
Williams Partners | Gulfstream Natural Gas System LLC
Schedule of Equity Method Investments [Line Items]
Percent interest in Gulfstream	49.00%		49.00%
Gulfstream Natural Gas System LLC
Schedule of Equity Method Investments [Line Items]
Cash received on contributing interest in equity method investee to WPZ	297
Contribution of equity earnings in Gulfstream	4	7	12	15	32	30	27
Gulfstream Natural Gas System LLC | Other
Schedule of Equity Method Investments [Line Items]
Percent interest in Gulfstream	1.00%		1.00%
Gulfstream Natural Gas System LLC | Intercompany Transfer
Schedule of Equity Method Investments [Line Items]
Percent interest in Gulfstream	24.50%		24.50%
Gulfstream Natural Gas System LLC | Williams Partners L.P.
Schedule of Equity Method Investments [Line Items]
Number of limited partner units received on contributing interest in equity method investee to WPZ	632,584
General Partners | Williams Partners L.P.
Schedule of Equity Method Investments [Line Items]
Ownership interest in subsidiary	2.00%		2.00%
Williams Partners
Schedule of Equity Method Investments [Line Items]
Impact on segment profit for all periods	2.50%	2.50%	2.50%	2.50%	2.50%	2.50%	2.50%
Contribution of equity earnings in Gulfstream	36	27	61	53
Other [Member]
Schedule of Equity Method Investments [Line Items]
Contribution of equity earnings in Gulfstream	$ 4	$ 7	$ 13	$ 16
Transcontinental Gas Pipe Line Company, LLC
Schedule of Equity Method Investments [Line Items]
Ownership interest in subsidiary	100.00%		100.00%
Williams Partners L.P.
Schedule of Equity Method Investments [Line Items]
Ownership interest in subsidiary	75.00%		75.00%
Northwest Pipeline GP
Schedule of Equity Method Investments [Line Items]
Ownership interest in subsidiary	100.00%		100.00%