Investments (Fair Values And Unrealized Losses By Investment Category And By The Duration Of The Securities' Continuous Unrealized Loss Position) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Investments, Unrealized Loss Position
Less than 12 months fair value	$ 393	$ 1,516
Less than 12 months unrealized losses	11	74
12 months or more fair value	446	86
12 months or more unrealized losses	11	5
Total fair value	839	1,602
Total unrealized losses	22	79
Fixed Maturities
Investments, Unrealized Loss Position
Less than 12 months fair value	292	1,397
Less than 12 months unrealized losses	8	70
12 months or more fair value	429	86
12 months or more unrealized losses	10	5
Total fair value	721	1,483
Total unrealized losses	18	75
Fixed Maturities | Corporate Securities
Investments, Unrealized Loss Position
Less than 12 months fair value	261	572
Less than 12 months unrealized losses	8	20
12 months or more fair value	90	43
12 months or more unrealized losses	3	2
Total fair value	351	615
Total unrealized losses	11	22
Fixed Maturities | States, Municipalities and Political Subdivisions
Investments, Unrealized Loss Position
Less than 12 months fair value	17	490
Less than 12 months unrealized losses	0	18
12 months or more fair value	135	42
12 months or more unrealized losses	2	3
Total fair value	152	532
Total unrealized losses	2	21
Fixed Maturities | Commercial Mortgage Backed Securities
Investments, Unrealized Loss Position
Less than 12 months fair value	3	125
Less than 12 months unrealized losses	0	5
12 months or more fair value	23	0
12 months or more unrealized losses	0	0
Total fair value	26	125
Total unrealized losses	0	5
Fixed Maturities | Government-Sponsored Enterprises
Investments, Unrealized Loss Position
Less than 12 months fair value	11	199
Less than 12 months unrealized losses	0	27
12 months or more fair value	181	1
12 months or more unrealized losses	5	0
Total fair value	192	200
Total unrealized losses	5	27
Fixed Maturities | Foreign Government
Investments, Unrealized Loss Position
Less than 12 months fair value		10
Less than 12 months unrealized losses		0
12 months or more fair value		0
12 months or more unrealized losses		0
Total fair value		10
Total unrealized losses		0
Fixed Maturities | United States Government
Investments, Unrealized Loss Position
Less than 12 months fair value		1
Less than 12 months unrealized losses		0
12 months or more fair value		0
12 months or more unrealized losses		0
Total fair value		1
Total unrealized losses		0
Equity Securities
Investments, Unrealized Loss Position
Less than 12 months fair value	101	119
Less than 12 months unrealized losses	3	4
12 months or more fair value	17	0
12 months or more unrealized losses	1	0
Total fair value	118	119
Total unrealized losses	4	4
Equity Securities | Common Equities
Investments, Unrealized Loss Position
Less than 12 months fair value	85	77
Less than 12 months unrealized losses	3	1
12 months or more fair value	0	0
12 months or more unrealized losses	0	0
Total fair value	85	77
Total unrealized losses	3	1
Equity Securities | Nonredeemable Preferred Equities
Investments, Unrealized Loss Position
Less than 12 months fair value	16	42
Less than 12 months unrealized losses	0	3
12 months or more fair value	17	0
12 months or more unrealized losses	1	0
Total fair value	33	42
Total unrealized losses	$ 1	$ 3