Derivatives (Embedded Derivatives) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within asset host contracts	$ 286	$ 171
Net embedded derivatives within liability host contracts	2,427	935
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	439	356
Direct guaranteed minimum benefits | Policyholder account balances [Member]
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within liability host contracts	992	(20)
Funds withheld on assumed reinsurance | Other invested assets
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within asset host contracts	49	35
Assumed guaranteed minimum benefits | Policyholder account balances [Member]
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within liability host contracts	1,392	965
Funds withheld on ceded reinsurance | Other liabilities
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within liability host contracts	42	(14)
Other | Policyholder account balances [Member]
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within liability host contracts	1	4
Options embedded in debt or equity securities [Member] | Investments
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Net embedded derivatives within asset host contracts	$ (202)	$ (220)