Derivatives - Gain (loss) included in the Statement of Earnings for changes in the fair value of derivatives that do not qualify for hedge accounting (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative		$ (6)	$ (12)	$ (21)	$ (54)
MBS with embedded derivatives | Realized gains (losses) on securities
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative		(3)	0	(8)	(3)
Public company warrants | Realized gains (losses) on securities
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative		1	(1)	0	(1)
Fixed-indexed and variable-indexed annuities (embedded derivative) | Annuity benefits
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative	[1]	(223)	(127)	(286)	(386)
Equity index call options | Annuity benefits
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative		219	116	271	338
Equity index put options | Annuity benefits
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative		0	0	0	0
Reinsurance contracts (embedded derivative) | Net investment income
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative		$ 0	$ 0	$ 2	$ (2)

[1] The change in fair value of the embedded derivative for the nine months ended September 30, 2018 includes a $44 million charge in the second quarter of 2018 related to the unlocking of actuarial assumptions.