Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Feb. 29, 2016	Dec. 31, 2015
CNA Financial [Member]
Commitments [Line Items]
Aggregate amount related to indemnification agreements		$ 260
Aggregate amount related to quantifiable guarantees		375
Potential amount of future payments under guarantees		2,000
Diamond Offshore Drilling, Inc. [Member] | Subsequent Event [Member] | Ge Oil And Gas [Member]
Commitments [Line Items]
Service agreement term	10 years
Diamond Offshore aggregate sale of equipment to GE affiliate	$ 210
Aggregate amount of future commitments under the services agreement and leases	$ 650
Harsh Environment Semisubmersible Drilling Rig [Member] | Diamond Offshore Drilling, Inc. [Member]
Commitments [Line Items]
Total cost of the project		764
Remaining contractual payment is due upon delivery of rig		$ 440