Summary Of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2010	Dec. 31, 2009
Summary Of Significant Accounting Policies [Line Items]
Amount of deferred marketing costs reported in deferred policy acquisition costs	$ 236	$ 253
Amortization expense for deferred marketing costs	128	115	103
Deferred marketing costs recoverability and amortized years	5
Reinsurance business assumed	35	92
Recoverable from unrated reinsurers, ceded reserve, default factor	25.00%
Borrowers collateral, percent of fair value loaned securities	102.00%
Maximum overdraft balance guaranteed	350
Goodwill impairment testing, qualitative assessment, percentage probability	50.00%
Finite lived intangible assets, amortized over useful lives, minimum in years	4
Finite lived intangible assets, amortized over useful lives, maximum in years	20
Net loss and loss expense reserves, net of discount held	59
Gross liability for amount due to claimants	644
Reinsurance recoverables	585
Structured settlements included in other assets	59
Deposit assets	133	144
Deposit liabilities include reinsurance deposit liabilities	318	351
Contract holder deposit funds	345	70
Net operating results of ESIS included within administrative expenses	21	85	26
Recognized income tax positions, percentage	50.00%
Decrease in Retained earnings	7,511	5,926
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Coverage terms of related reinsurance contracts and range in years	1
Reinsurance business, payment pattern of the losses assumed and range years	7
Interest rates used in calculating reserves	1.00%	1.00%
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Coverage terms of related reinsurance contracts and range in years	3
Reinsurance business, payment pattern of the losses assumed and range years	40
Interest rates used in calculating reserves	6.00%	7.00%
Accounting For Costs Associated With Acquiring Or Renewing Insurance Contracts [Member]
Summary Of Significant Accounting Policies [Line Items]
Decrease in Retained earnings	$ 188