Derivative Financial Instruments (Details 4) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Settlement Payments By Hedge Classification And Income Statement Location
Settlement Payments	$ 12	$ 71
Derivatives Designated as Hedging Instruments [Member] | Net Investment Income [Member]
Settlement Payments By Hedge Classification And Income Statement Location
Settlement Payments	24	22
Derivatives Designated as Hedging Instruments [Member] | Interest Credited to Policyholder Account Balance [Member]
Settlement Payments By Hedge Classification And Income Statement Location
Settlement Payments	45	61
Derivatives Designated as Hedging Instruments [Member] | Other Expenses [Member]
Settlement Payments By Hedge Classification And Income Statement Location
Settlement Payments	(1)	(1)
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net Investment Income [Member]
Settlement Payments By Hedge Classification And Income Statement Location
Settlement Payments	(1)	(1)
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Other Revenues [Member]
Settlement Payments By Hedge Classification And Income Statement Location
Settlement Payments	18	15
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net Derivative Gain (Losses) [Member]
Settlement Payments By Hedge Classification And Income Statement Location
Settlement Payments	(11)	(27)
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Policyholder Benefit and Claim [Member]
Settlement Payments By Hedge Classification And Income Statement Location
Settlement Payments	$ (62)	$ 2