Derivatives (Embedded Derivatives) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within asset host contracts	$ 243	$ 171
Embedded derivatives within liability host contracts	4,105	935
Ceded guaranteed minimum benefits | Premiums, reinsurance and other receivables
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within asset host contracts	380	356
Direct guaranteed minimum benefits | Policyholder account balances [Member]
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	2,720	(20)
Funds withheld on assumed reinsurance | Other invested assets
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within asset host contracts	0	35
Assumed guaranteed minimum benefits | Policyholder account balances [Member]
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	1,205	965
Funds withheld on ceded reinsurance | Other liabilities
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	(30)	(14)
Fixed annuities with equity indexed returns | Policyholder account balances [Member]
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	210	4
Options embedded in debt or equity securities [Member] | Investments
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within asset host contracts	$ (137)	$ (220)