Drilling Fleet (Details 2) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended			3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Sell of Standard Jackup and swamp barge market sectors drillingunit	Sep. 30, 2012 Deepwater Floaters Discoverer 534 and Jim Cunningham	Sep. 30, 2012 Deepwater Floaters Discoverer 534 and Jim Cunningham	Sep. 30, 2011 Overseas Drilling Limited	Sep. 30, 2011 Overseas Drilling Limited	Jul. 31, 2011 Overseas Drilling Limited	Sep. 30, 2012 Sale of Other Assets	Sep. 30, 2011 Sale of Other Assets	Sep. 30, 2012 Sale of Other Assets	Sep. 30, 2011 Sale of Other Assets
Dispositions
Net cash proceeds from sale of assets	$ 178	$ 4	$ 189	$ 12		$ 178	$ 178
Net cash proceeds from sale of assets								22	22
Gain (loss) on the sale of assets	50	(1)	40	(1)		51	51				1	1	11	3
Gain (loss) on the sale of assets								13	13
Gain (loss) on the sale of assets, net of tax						$ 48	$ 48
Aggregate losses on impairment of assets per diluted share								$ 0.04	$ 0.04
Gain (loss) on the sale of assets per diluted share						$ 0.13	$ 0.13
Ownership interest in affiliate (as a percent)										50.00%
Number of Standard Jackups sell					46
Number of Swamp barge sell					1