Investments (Schedule Of Fixed Maturities By Contractual Maturity) (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Investments, Debt and Equity Securities [Abstract]
Available for sale, Due in 1 year or less, Amortized Cost	$ 2,504	$ 2,387
Available for sale, Due after 1 year through 5 years, Amortized Cost	14,199	14,139
Available for sale, Due after 5 years though 10 years, Amortized Cost	15,947	16,200
Available for sale, Due after 10 years, Amortized Cost	4,716	4,743
Available for sale, Subtotal, Amortized Cost	37,366	37,469
Available for sale, Mortgage-backed securities, Amortized Cost	10,916	10,937
Available for sale, Amortized Cost	48,282	48,406
Available for sale, Fair Value	49,611	49,254
Held to maturity, Due in 1 year or less, Amortized Cost	539	401
Held to maturity, Due after 1 year through 5 years, Amortized Cost	2,419	2,284
Held to maturity, Due after 5 years through 10 years, Amortized Cost	1,304	1,686
Held to maturity, Due after 10 years, Amortized Cost	360	386
Held to maturity, Subtotal, Amortized Cost	4,622	4,757
Held to maturity, Mortgage backed securities, Amortized Cost	1,265	1,341
Available for sale, Due in 1 year or less, Fair Value	2,528	2,411
Available for sale, Due after 1 year through 5 years, Fair Value	14,713	14,602
Available for sale, Due after 5 years through 10 years, Fair Value	16,460	16,535
Available for sale, Due after 10 years, Fair Value	4,939	4,812
Available for sale, Subtotal, Fair Value	38,640	38,360
Available for sale, Mortgage backed securities, Fair Value	10,971	10,894
Held to maturity, Due in 1 year or less, Fair Value	547	405
Held to maturity, Due after 1 year through 5, Fair Value	2,503	2,363
Held to maturity, Due after 5 years through 10 years, Fair Value	1,345	1,723
Held to maturity, Due after 10 years, Fair Value	379	393
Held to maturity, Subtotal, Fair Value	4,774	4,884
Held to maturity, Mortgage backed securities, Fair Value	1,306	1,379
Held-to-maturity Securities	5,887	6,098
Held to maturity, Fair Value	$ 6,080	$ 6,263