Commitments - Operating Leases (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due	$ 3,061,000,000
Operating leases, residual value guarantees	53,000,000
Operating leases, residual value guarantees accrued	0
Total rent expense, net of sublease income and amounts capitalized	85,000,000	119,000,000	136,000,000
Contingent rent expense	22,000,000	24,000,000	28,000,000
Maximum [Member]
Operating Leased Assets [Line Items]
Operating leases, expiration date	Dec. 31, 2026
Drilling Rigs [Member]
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due	2,700,000,000
Other Operating Lease Agreements [Member]
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due	324,000,000
Offshore Drilling Rig Commitments [Member]
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due	2,500,000,000
Number of offshore drilling vessels related to operating leases	7
Onshore Drilling Rig Commitments [Member]
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due	$ 208,000,000