Derivatives (Embedded Derivatives) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	$ 2,946	$ 2,516
Premiums, reinsurance and other receivables | Ceded guaranteed minimum income benefits
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within asset host contracts	219	228
Policyholder account balances | Fixed Annuity
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	1,249	488
Policyholder account balances | Fixed Annuity | Assumed index-linked annuities
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	146	96
Policyholder account balances | Direct Guaranteed Minimum Benefit
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	1,170	1,546
Policyholder account balances | Assumed guaranteed minimum benefits
Embedded Derivative, Fair Value of Embedded Derivative, Net [Abstract]
Embedded derivatives within liability host contracts	$ 381	$ 386