Commitments - Operating Leases (Detail)	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due	$ 2,117,000,000
Operating leases, residual value guarantees	81,000,000
Operating leases, residual value guarantees accrued	0
Total rent expense, net of sublease income and amounts capitalized	77,000,000	$ 85,000,000	$ 119,000,000
Contingent rent expense	$ 17,000,000	$ 22,000,000	$ 24,000,000
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	$ 1,800,000,000.0
Other Operating Lease Agreements [Member]
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due	329,000,000
Offshore Drilling Rig Commitments [Member]
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due	$ 1,700,000,000
Number of offshore drilling vessels related to operating leases	5
Onshore Drilling Rig Commitments [Member]
Operating Leased Assets [Line Items]
Operating leases, future minimum payments due	$ 98,000,000