Variable Interest Entities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Number of Instruments	4	4
Notional Amounts	$ 600	$ 600
Carrying Value	128	291
Unconsolidated VIE long term senior note	500
Excess mortality swap note	100
Fixed maturity corporate asset-backed credit card loan securities [Member]
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Notional Amounts	0	0
Carrying Value	598	592
Credit default swaps [Member]
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Number of Instruments	2	2
Notional Amounts	600	600
Carrying Value	129	295
Contingent Forwards [Member]
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Number of Instruments	2	2
Notional Amounts	0	0
Carrying Value	(1)	(4)
Federal Income Tax Liability [Member]
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Notional Amounts	0	0
Carrying Value	(36)	(98)
U.S. government bonds [Member]
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Notional Amounts	0	0
Carrying Value	110	108
Excess mortality swap [Member]
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Number of Instruments	1	1
Notional Amounts	100	100
Carrying Value	0	0
Assets Variable Interest Entities [Member]
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Number of Instruments	1	1
Notional Amounts	100	100
Carrying Value	708	700
Liabilities Variable Interest Entities [Member]
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Number of Instruments	4	4
Notional Amounts	600	600
Carrying Value	$ 92	$ 193