Derivatives (Embedded Derivatives) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within asset host contracts	$ 240	$ 222
Net embedded derivatives within liability host contracts	960	617
Ceded guaranteed minimum benefits | Premiums, reinsurance and other receivables
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within asset host contracts	242	217
Funds withheld on assumed reinsurance | Other invested assets
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within asset host contracts	56	53
Direct guaranteed minimum benefits | Policyholder account balances
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within liability host contracts	(410)	(609)
Assumed guaranteed minimum benefits | Policyholder account balances
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within liability host contracts	893	827
Funds withheld on ceded reinsurance | Other liabilities
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within liability host contracts	458	382
Other | Policyholder account balances
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within liability host contracts	19	17
Options embedded in debt or equity securities | Investments
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within asset host contracts	$ (58)	$ (48)