Quarterly Results (Unaudited) (Details) (USD $) Share data in Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Quarterly Results (Unaudited)
Operating revenues	$ 2,422,000,000	$ 2,242,000,000	$ 2,334,000,000	$ 2,144,000,000	$ 2,127,000,000	$ 2,281,000,000	$ 2,479,000,000	$ 2,579,000,000	$ 9,142,000,000	$ 9,466,000,000	$ 11,441,000,000
Operating income (loss)	(5,807,000,000)	268,000,000	391,000,000	372,000,000	(668,000,000)	634,000,000	949,000,000	942,000,000	(4,776,000,000)	1,857,000,000	4,390,000,000
Income (loss) from continuing operations	(6,102,000,000)	(53,000,000)	162,000,000	164,000,000	(804,000,000)	363,000,000	712,000,000	683,000,000	(5,829,000,000)	954,000,000	3,196,000,000
Net income (loss) attributable to controlling interest	(6,119,000,000)	(71,000,000)	155,000,000	310,000,000	(799,000,000)	368,000,000	715,000,000	677,000,000	(5,725,000,000)	961,000,000	3,181,000,000
Earnings (loss) per share
Basic (in dollars per share)	$ (18.70)	$ (0.20)	$ 0.47	$ 0.42	$ (2.53)	$ 1.10	$ 2.20	$ 2.09	$ (17.79)	$ 2.99	$ 9.87
Diluted (in dollars per share)	$ (18.70)	$ (0.20)	$ 0.47	$ 0.42	$ (2.53)	$ 1.10	$ 2.20	$ 2.08	$ (17.79)	$ 2.99	$ 9.84
Weighted-average shares outstanding
Basic: (in shares)	329	320	320	319	319	319	319	321	322	320	320
Diluted: (in shares)	329	320	320	320	319	319	320	322	322	320	321
Gain on the loss of Deepwater Horizon							267,000,000			267,000,000
Loss on impairment					1,000,000,000				5,229,000,000	1,010,000,000	334,000,000
Impairment	5,200,000,000								5,200,000,000
Loss recognized during the period		78,000,000
Loss associated with the Macondo well incident contingencies	1,000,000,000
Gains (losses) on disposal of discontinued operations	$ 12,000,000	$ (4,000,000)		$ 173,000,000					$ 181,000,000