Invested Assets - Fair Value and Amortized Cost of Fixed Maturities by Contractual Maturity (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule of Available-For-Sale Securities [Line Items]
Due in one year or less, Fair Value	$ 1,967
Due after one year through five years, Fair Value	14,182
Due after five years through ten years, Fair Value	12,348
Due after ten years, Fair Value	8,108
Subtotal fixed maturities, Fair Value	36,605
Total fixed maturities, Fair Value	38,062	37,091
Due in one year or less, Amortized Cost	1,946
Due after one year through five years, Amortized Cost	13,577
Due after five years through ten years, Amortized Cost	11,661
Due after ten years, Amortized Cost	7,720
Subtotal fixed maturities, Amortized Cost	34,904
Total fixed maturities, Amortized Cost	36,313	35,959
Residential Mortgage-backed Securities [Member]
Schedule of Available-For-Sale Securities [Line Items]
Taxable, Fair Value	250
Taxable, Amortized Cost	229
Commercial Mortgage-backed Securities [Member]
Schedule of Available-For-Sale Securities [Line Items]
Taxable, Fair Value	1,207
Taxable, Amortized Cost	$ 1,180