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	Mar. 31, 2014	Dec. 31, 2013
Investment [Line Items]
Held to maturity, Amortized Cost	$ 5,887	$ 6,098
Held to maturity, Gross Unrealized Appreciation	207	187
Held to maturity, Gross Unrealized Depreciation	(14)	(22)
Held to maturity, Fair Value	6,080	6,263
Held to maturity, OTTI recognized in AOCI
Available for sale, Amortized Cost	48,282	48,406
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	1,697	1,465
Available for sale, Gross Unrealized Depreciation	(368)	(617)
Available for sale, Fair Value	49,611	49,254
Available for sale, OTTI recognized in AOCI	(34)	(40)
U.S. Treasury And Agency [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	777	820
Held to maturity, Gross Unrealized Appreciation	17	16
Held to maturity, Gross Unrealized Depreciation	(4)	(4)
Held to maturity, Fair Value	790	832
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	2,939	2,946
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	68	62
Available for sale, Gross Unrealized Depreciation	(37)	(59)
Available for sale, Fair Value	2,970	2,949
Available for sale, OTTI recognized in AOCI	0	0
Foreign [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	837	864
Held to maturity, Gross Unrealized Appreciation	37	33
Held to maturity, Gross Unrealized Depreciation	0	0
Held to maturity, Fair Value	874	897
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	14,155	14,336
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	441	377
Available for sale, Gross Unrealized Depreciation	(65)	(122)
Available for sale, Fair Value	14,531	14,591
Available for sale, OTTI recognized in AOCI	(1)	0
Corporate Securities [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	1,876	1,922
Held to maturity, Gross Unrealized Appreciation	89	83
Held to maturity, Gross Unrealized Depreciation	0	0
Held to maturity, Fair Value	1,965	2,005
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	16,873	16,825
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	883	777
Available for sale, Gross Unrealized Depreciation	(71)	(132)
Available for sale, Fair Value	17,685	17,470
Available for sale, OTTI recognized in AOCI	(6)	(6)
Mortgage Backed-Securities [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	1,265	1,341
Held to maturity, Gross Unrealized Appreciation	41	39
Held to maturity, Gross Unrealized Depreciation	0	(1)
Held to maturity, Fair Value	1,306	1,379
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	10,916	10,937
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	210	184
Available for sale, Gross Unrealized Depreciation	(155)	(227)
Available for sale, Fair Value	10,971	10,894
Available for sale, OTTI recognized in AOCI	(27)	(34)
States, Municipalities, And Political Subdivisions [Member]
Investment [Line Items]
Held to maturity, Amortized Cost	1,132	1,151
Held to maturity, Gross Unrealized Appreciation	23	16
Held to maturity, Gross Unrealized Depreciation	(10)	(17)
Held to maturity, Fair Value	1,145	1,150
Held to maturity, OTTI recognized in AOCI	0	0
Available for sale, Amortized Cost	3,399	3,362
AvailableforsaleSecuritiesGrossUnrealizedGainAccumulatedInInvestments	95	65
Available for sale, Gross Unrealized Depreciation	(40)	(77)
Available for sale, Fair Value	3,454	3,350
Available for sale, OTTI recognized in AOCI	$ 0	$ 0