Income Taxes - Total income tax provision (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current taxes:
Federal	$ 196	$ 153	$ 299
State	8	6	12
Deferred taxes:
Federal	(82)	5	(192)
Impact of change in U.S. corporate tax rate	0	83	0
Total Federal deferred taxes	(82)	88	(192)
Provision for income taxes as shown in the Statement of Earnings	$ 122	$ 247	$ 119