Income Taxes (Reconciliation between the Company's federal income tax (expense) benefit at statutory rates and the recorded income tax (expense) benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income tax expense at statutory rates	$ (203)	$ (459)	$ (398)
Tax benefit from tax exempt income	63	131	124
Foreign taxes and credits	(1)	3	3
State income taxes	(13)	(7)	(6)
Net deferred tax asset remeasurement	6	(83)	0
Other tax expense	(3)	4	(1)
Income tax expense	$ (151)	$ (411)	$ (278)