CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Operating revenues
Contract drilling revenues	$ 2,310	$ 1,827	$ 6,498	$ 5,396
Other revenues	130	164	420	576
Total operating revenues	2,440	1,991	6,918	5,972
Costs and expenses
Operating and maintenance	1,338	1,344	4,731	3,915
Depreciation and amortization	280	281	846	821
General and administrative	69	67	217	200
Total costs and expenses	1,687	1,692	5,794	4,936
Loss on impairment			(210)
Gain (loss) on disposal of assets, net	50	(1)	40	(1)
Operating income	803	298	954	1,035
Other income (expense), net
Interest income	15	7	43	27
Interest expense, net of amounts capitalized	(180)	(151)	(543)	(443)
Other, net	(8)	(77)	(32)	(79)
Total other income (expense), net	(173)	(221)	(532)	(495)
Income from continuing operations before income tax expense	630	77	422	540
Income tax expense	104	93	96	211
Income (loss) from continuing operations	526	(16)	326	329
Income (loss) from discontinued operations, net of tax	(909)	(5)	(994)	116
Net income (loss)	(383)	(21)	(668)	445
Net income (loss) attributable to noncontrolling interest	(2)	11	7	34
Net income (loss) attributable to controlling interest	$ (381)	$ (32)	$ (675)	$ 411
Earnings (loss) per share-basic
Earnings (loss) from continuing operations (in dollars per share)	$ 1.47	$ (0.08)	$ 0.90	$ 0.92
Earnings (loss) from discontinued operations (in dollars per share)	$ (2.53)	$ (0.02)	$ (2.80)	$ 0.36
Earnings (loss) per share (in dollars per share)	$ (1.06)	$ (0.10)	$ (1.90)	$ 1.28
Earnings (loss) per share-diluted
Earnings (loss) from continuing operations (in dollars per share)	$ 1.47	$ (0.08)	$ 0.90	$ 0.92
Earnings (loss) from discontinued operations (in dollars per share)	$ (2.53)	$ (0.02)	$ (2.80)	$ 0.36
Earnings (loss) per share (in dollars per share)	$ (1.06)	$ (0.10)	$ (1.90)	$ 1.28
Weighted-average shares outstanding
Basic (in shares)	359	320	354	320
Diluted (in shares)	359	320	354	320