Invested Assets - Fair Value and Amortized Cost of Fixed Maturities by Contractual Maturity (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-For-Sale Securities [Line Items]
Due in one year or less, Fair Value	$ 2,311
Due after one year through five years, Fair Value	14,107
Due after five years through ten years, Fair Value	11,959
Due after ten years, Fair Value	7,917
Subtotal fixed maturities, Fair Value	36,294
Total fixed maturities, Fair Value	37,825	37,091
Due in one year or less, Amortized Cost	2,284
Due after one year through five years, Amortized Cost	13,487
Due after five years through ten years, Amortized Cost	11,413
Due after ten years, Amortized Cost	7,664
Subtotal fixed maturities, Amortized Cost	34,848
Total fixed maturities, Amortized Cost	36,331	35,959
Residential Mortgage-backed Securities [Member]
Schedule of Available-For-Sale Securities [Line Items]
Taxable, Fair Value	273
Taxable, Amortized Cost	251
Commercial Mortgage-backed Securities [Member]
Schedule of Available-For-Sale Securities [Line Items]
Taxable, Fair Value	1,258
Taxable, Amortized Cost	$ 1,232