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		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative		$ (36)	$ (35)	$ (15)	$ (42)
MBS with embedded derivatives | Realized gains (losses) on securities
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative		(1)	(3)	(5)	(3)
Public company warrants | Realized gains (losses) on securities
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative		0	0	(1)	0
Fixed-indexed and variable-indexed annuities (embedded derivative) | Annuity benefits
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative	[1]	(126)	(112)	(63)	(259)
Equity index call options | Annuity benefits
Derivative, Gain (Loss) on Derivative, Net [Abstract]
Derivative		90	81	52	222
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		$ 1	$ (1)	$ 2	$ (2)

[1] The change in fair value of the embedded derivative includes losses related to unlocking of actuarial assumptions of $44 million in both the second quarter and first six months of 2018