Investments (Details 1) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
U.S. Government and government agencies [Member]
Available for sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	$ (3)	$ (3)
Fair Value - Less than twelve months	38	60
Fair Value as % of Cost - Less than twelve months	93.00%	95.00%
Unrealized Loss - Twelve months or more	0	0
Fair Value - Twelve months or more	0	0
Fair Value as % of Cost - Twelve months or more	0.00%	0.00%
States, municipalities and political subdivisions [Member]
Available for sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	(64)	(135)
Fair Value - Less than twelve months	1,523	2,219
Fair Value as % of Cost - Less than twelve months	96.00%	94.00%
Unrealized Loss - Twelve months or more	(6)	(9)
Fair Value - Twelve months or more	90	73
Fair Value as % of Cost - Twelve months or more	94.00%	89.00%
Residential Mortgage Backed Securities [Member]
Available for sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	(8)	(9)
Fair Value - Less than twelve months	494	553
Fair Value as % of Cost - Less than twelve months	98.00%	98.00%
Unrealized Loss - Twelve months or more	(16)	(19)
Fair Value - Twelve months or more	214	212
Fair Value as % of Cost - Twelve months or more	93.00%	92.00%
Commercial Mortgage Backed Securities [Member]
Available for sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	(1)	(3)
Fair Value - Less than twelve months	48	106
Fair Value as % of Cost - Less than twelve months	98.00%	97.00%
Unrealized Loss - Twelve months or more	0	0
Fair Value - Twelve months or more	2	2
Fair Value as % of Cost - Twelve months or more	100.00%	100.00%
Asset-backed Securities [Member]
Available for sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	(14)	(18)
Fair Value - Less than twelve months	1,101	1,310
Fair Value as % of Cost - Less than twelve months	99.00%	99.00%
Unrealized Loss - Twelve months or more	(2)	(1)
Fair Value - Twelve months or more	44	28
Fair Value as % of Cost - Twelve months or more	96.00%	97.00%
All other corporate [Member]
Available for sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	(44)	(101)
Fair Value - Less than twelve months	1,506	2,634
Fair Value as % of Cost - Less than twelve months	97.00%	96.00%
Unrealized Loss - Twelve months or more	(5)	(7)
Fair Value - Twelve months or more	86	85
Fair Value as % of Cost - Twelve months or more	95.00%	92.00%
Fixed maturities [Member]
Available for sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	(134)	(269)
Fair Value - Less than twelve months	4,710	6,882
Fair Value as % of Cost - Less than twelve months	97.00%	96.00%
Unrealized Loss - Twelve months or more	(29)	(36)
Fair Value - Twelve months or more	436	400
Fair Value as % of Cost - Twelve months or more	94.00%	92.00%
Common stocks [Member]
Available for sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	(12)	(16)
Fair Value - Less than twelve months	166	158
Fair Value as % of Cost - Less than twelve months	93.00%	91.00%
Unrealized Loss - Twelve months or more	0	0
Fair Value - Twelve months or more	0	0
Fair Value as % of Cost - Twelve months or more	0.00%	0.00%
Perpetual preferred stocks [Member]
Available for sale securities in a continuous unrealized loss position
Unrealized Loss - Less than twelve months	(4)	(6)
Fair Value - Less than twelve months	90	91
Fair Value as % of Cost - Less than twelve months	96.00%	94.00%
Unrealized Loss - Twelve months or more	(1)	(4)
Fair Value - Twelve months or more	$ 6	$ 20
Fair Value as % of Cost - Twelve months or more	86.00%	83.00%