Income Taxes (Details 1) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Taxes on Continuing Operations (Table Amounts)
Current federal income tax expense (benefit)	$ 449	$ 661	$ 310
Deferred federal income tax expense (benefit)	581	49	472
Total federal income tax expense (benefit)	1,030	710	782
Current foreign income tax expense (benefit)	8	14	21
Deferred foreign income tax expense (benefit)	(4)	(1)	(3)
Total foreign income tax expense (benefit)	4	13	18
Total federal and foreign income tax expense	$ 1,034	$ 723	$ 800