Investments (Schedule Of Amortized Cost And Fair Value Of Fixed Maturities And Related Other-Than-Temporary Impairment Recognized In Accumulated Other Comprehensive Income) (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Investment [Line Items]
Held to maturity, Amortized Cost	$ 5,774	$ 6,098
Held to maturity, Gross Unrealized Appreciation	248	187
Held to maturity, Gross Unrealized Depreciation	(7)	(22)
Held to maturity, Fair Value	6,015	6,263
Held to maturity, OTTI recognized in AOCI
Available for sale, Amortized Cost	49,719	48,406
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	2,063	1,465
Available for sale, Gross Unrealized Depreciation	(181)	(617)
Available for sale, Fair Value	51,601	49,254
Available for sale, OTTI recognized in AOCI	(14)	(40)
U.S. Treasury And Agency [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	779	820
Held to maturity, Gross Unrealized Appreciation	18	16
Held to maturity, Gross Unrealized Depreciation	(2)	(4)
Held to maturity, Fair Value	795	832
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	2,806	2,946
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	80	62
Available for sale, Gross Unrealized Depreciation	(17)	(59)
Available for sale, Fair Value	2,869	2,949
Available for sale, OTTI recognized in AOCI	0	0
Foreign [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	809	864
Held to maturity, Gross Unrealized Appreciation	44	33
Held to maturity, Gross Unrealized Depreciation	0	0
Held to maturity, Fair Value	853	897
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	15,084	14,336
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	563	377
Available for sale, Gross Unrealized Depreciation	(38)	(122)
Available for sale, Fair Value	15,609	14,591
Available for sale, OTTI recognized in AOCI	(1)	0
Corporate Securities [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	1,828	1,922
Held to maturity, Gross Unrealized Appreciation	101	83
Held to maturity, Gross Unrealized Depreciation	0	0
Held to maturity, Fair Value	1,929	2,005
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	17,085	16,825
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	981	777
Available for sale, Gross Unrealized Depreciation	(36)	(132)
Available for sale, Fair Value	18,030	17,470
Available for sale, OTTI recognized in AOCI	(3)	(6)
Mortgage Backed-Securities [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	1,187	1,341
Held to maturity, Gross Unrealized Appreciation	54	39
Held to maturity, Gross Unrealized Depreciation	0	(1)
Held to maturity, Fair Value	1,241	1,379
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	11,185	10,937
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	308	184
Available for sale, Gross Unrealized Depreciation	(75)	(227)
Available for sale, Fair Value	11,418	10,894
Available for sale, OTTI recognized in AOCI	(10)	(34)
States, Municipalities, And Political Subdivisions [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	1,171	1,151
Held to maturity, Gross Unrealized Appreciation	31	16
Held to maturity, Gross Unrealized Depreciation	(5)	(17)
Held to maturity, Fair Value	1,197	1,150
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	3,559	3,362
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	131	65
Available for sale, Gross Unrealized Depreciation	(15)	(77)
Available for sale, Fair Value	3,675	3,350
Available for sale, OTTI recognized in AOCI	$ 0	$ 0