Investments (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Available for sale fixed maturities and equity securities
Gross Unrealized, Losses	$ (305)
U.S. Government and government agencies [Member]
Available for sale fixed maturities and equity securities
Amortized Cost	310	373
Fair Value	314	388
Gross Unrealized, Gains	7	15
Gross Unrealized, Losses	(3)	0
States, municipalities and political subdivisions [Member]
Available for sale fixed maturities and equity securities
Amortized Cost	5,360	4,144
Fair Value	5,372	4,468
Gross Unrealized, Gains	156	329
Gross Unrealized, Losses	(144)	(5)
Foreign government [Member]
Available for sale fixed maturities and equity securities
Amortized Cost	198	242
Fair Value	208	260
Gross Unrealized, Gains	10	18
Gross Unrealized, Losses	0	0
Residential Mortgage Backed Securities [Member]
Available for sale fixed maturities and equity securities
Amortized Cost	3,947	3,921
Fair Value	4,310	4,204
Gross Unrealized, Gains	391	337
Gross Unrealized, Losses	(28)	(54)
Commercial Mortgage Backed Securities [Member]
Available for sale fixed maturities and equity securities
Amortized Cost	2,535	2,583
Fair Value	2,724	2,918
Gross Unrealized, Gains	192	335
Gross Unrealized, Losses	(3)	0
Asset-backed Securities [Member]
Available for sale fixed maturities and equity securities
Amortized Cost	2,477	1,590
Fair Value	2,493	1,640
Gross Unrealized, Gains	35	52
Gross Unrealized, Losses	(19)	(2)
All other corporate [Member]
Available for sale fixed maturities and equity securities
Amortized Cost	10,539	9,230
Fair Value	11,035	10,240
Gross Unrealized, Gains	604	1,015
Gross Unrealized, Losses	(108)	(5)
Fixed maturities [Member]
Available for sale fixed maturities and equity securities
Amortized Cost	25,366	22,083
Fair Value	26,456	24,118
Gross Unrealized, Gains	1,395	2,101
Gross Unrealized, Losses	(305)	(66)
Common stocks [Member]
Available for sale fixed maturities and equity securities
Amortized Cost	721	600
Fair Value	914	749
Gross Unrealized, Gains	209	157
Gross Unrealized, Losses	(16)	(8)
Perpetual preferred stocks [Member]
Available for sale fixed maturities and equity securities
Amortized Cost	266	178
Fair Value	265	190
Gross Unrealized, Gains	9	13
Gross Unrealized, Losses	$ (10)	$ (1)