Goodwill (details) - Other Intangible Assets (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	$ 661		$ 661
Intangible assets subject to amortization, accumulated amortization	539		527
Intangible assets subject to amortization, net	122		134
Amortization expense for other intangible assets	12	11
Estimated intangible asset amortization expense, remainder of 2014	35
Estimated intangible asset amortization expense, 2015	27
Estimated intangible asset amortization expense, 2016	10
Estimated intangible asset amortization expense, 2017	9
Estimated intangible asset amortization expense, 2018	8
Customer-related [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	460		460
Intangible assets subject to amortization, accumulated amortization	422		414
Intangible assets subject to amortization, net	38		46
Amortization expense for other intangible assets	8	7
Fair value adjustment on claims and claim adjustment expense reserves, reinsurance recoverables and other contract-related intangibles [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	201		201
Intangible assets subject to amortization, accumulated amortization	117		113
Intangible assets subject to amortization, net	84		88
Amortization expense for other intangible assets	$ 4	$ 4