Goodwill (details) - Other Intangible Assets (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	$ 1,126		$ 1,126		$ 1,126
Intangible assets subject to amortization, accumulated amortization	893		893		840
Intangible assets subject to amortization, net	233		233		286
Amortization expense for other intangible assets	16	21	53	66
Customer-related [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	935		935		935
Intangible assets subject to amortization, accumulated amortization	819		819		783
Intangible assets subject to amortization, net	116		116		152
Amortization expense for other intangible assets	11	14	36	46
Fair value adjustment on claims and claim adjustment expense reserves and reinsurance recoverables [Member]
Other intangible assets by major asset class
Intangible assets subject to amortization, gross carrying amount	191		191		191
Intangible assets subject to amortization, accumulated amortization	74		74		57
Intangible assets subject to amortization, net	117		117		134
Amortization expense for other intangible assets	$ 5	$ 7	$ 17	$ 20