Commitments (Detail) (Deepwater Drillship [Member], USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2013
Deepwater Drillship [Member]
Operating Leased Assets [Line Items]
Operating lease, period	3 years
Total future minimum lease payments	$ 464
Aggregate future annual minimum lease payments in 2014	104
Aggregate future annual minimum lease payments in 2015	154
Aggregate future annual minimum lease payments in 2016	155
Aggregate future annual minimum lease payments in 2017	$ 51

Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the forth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the third fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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- Definition

Amount of required minimum rental payments maturing in the second fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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