Invested Assets and Related Income - Fair Value and Amortized Cost of Foreign Government and Government Agency Fixed Maturities (Detail) (Foreign Government and Government Agency Obligations [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Canada [Member]
Schedule of Available-For-Sale Securities [Line Items]
Fair Value	$ 1,993	$ 2,157
Amortized Cost	1,953	2,060
Germany [Member]
Schedule of Available-For-Sale Securities [Line Items]
Fair Value	1,241	1,127
Amortized Cost	1,211	1,070
United Kingdom [Member]
Schedule of Available-For-Sale Securities [Line Items]
Fair Value	1,026	1,024
Amortized Cost	1,004	939
Australia [Member]
Schedule of Available-For-Sale Securities [Line Items]
Fair Value	739	742
Amortized Cost	700	663
Brazil [Member]
Schedule of Available-For-Sale Securities [Line Items]
Fair Value	270	310
Amortized Cost	$ 270	$ 310