Derivatives (Embedded Derivatives) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within asset host contracts	$ 5	$ 55
Embedded derivatives within liability host contracts	1,399	1,554
Ceded guaranteed minimum benefits | Premiums, reinsurance and other receivables
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within asset host contracts	145	143
Direct guaranteed minimum benefits | Policyholder account balances
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	99	361
Assumed guaranteed minimum benefits | Policyholder account balances
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	1,240	1,205
Funds withheld on ceded reinsurance | Other liabilities
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	6	(30)
Fixed annuities with equity indexed returns | Policyholder account balances
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	54	18
Options embedded in debt or equity securities [Member] | Other
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within asset host contracts	$ (140)	$ (88)