Segment Disclosures (Details) (USD $) In Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Segment revenues:
Segment revenues, External	$ 2,669	$ 2,289	$ 5,244	$ 4,880
Total revenues	2,669	2,289	5,244	4,880
Segment profit (loss)	639	513	1,221	1,117
Less: Equity earnings (losses)	45	39	85	79
Less: Income (loss) from investments		13	11	13
Segment operating income (loss)	594	461	1,125	1,025
General corporate expenses	(47)	(45)	(98)	(130)
Total operating income (loss)	547	416	1,027	895
Total assets by reporting segment
Total assets	25,705		25,705		24,972
Williams Partners
Segment revenues:
Segment revenues, External	1,557	1,307	3,035	2,704
Segment revenues, Internal	114	93	215	186
Total revenues	1,671	1,400	3,250	2,890
Segment profit (loss)	471	361	908	785
Less: Equity earnings (losses)	36	27	61	53
Segment operating income (loss)	435	334	847	732
Total operating income (loss)	435	334	847	732
Total assets by reporting segment
Total assets	13,723		13,723		13,404
Exploration & Production
Segment revenues:
Segment revenues, External	762	726	1,541	1,651
Segment revenues, Internal	219	175	429	407
Total revenues	981	901	1,970	2,058
Segment profit (loss)	94	73	145	226
Less: Equity earnings (losses)	5	5	11	10
Segment operating income (loss)	89	68	134	216
Total operating income (loss)	89	68	134	216
Total assets by reporting segment
Total assets	9,778		9,778		9,827
Midstream Canada & Olefins
Segment revenues:
Segment revenues, External	345	254	661	521
Segment revenues, Internal	2	3	2	8
Total revenues	347	257	663	529
Segment profit (loss)	72	61	146	81
Segment operating income (loss)	72	61	146	81
Total operating income (loss)	72	61	146	81
Total assets by reporting segment
Total assets	1,052		1,052		922
Other [Member]
Segment revenues:
Segment revenues, External	5	2	7	4
Segment revenues, Internal	2	3	6	7
Total revenues	7	5	13	11
Segment profit (loss)	2	18	22	25
Less: Equity earnings (losses)	4	7	13	16
Less: Income (loss) from investments		13	11	13
Segment operating income (loss)	(2)	(2)	(2)	(4)
Total operating income (loss)	(2)	(2)	(2)	(4)
Total assets by reporting segment
Total assets	1,478		1,478		3,481
Business Intersegment Eliminations
Segment revenues:
Segment revenues, Internal	(337)	(274)	(652)	(608)
Total revenues	(337)	(274)	(652)	(608)
Total assets by reporting segment
Total assets	$ (326)		$ (326)		$ (2,662)