Income Taxes - Components of Income Tax Expense (Benefit) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Current Federal Tax Expense (Benefit)	$ (956)	$ (686)	$ (653)
Current State and Local Tax Expense (Benefit)	(13)	(9)	(3)
Current foreign	81	104	83
Current Income Tax Expense (Benefit)	(888)	(591)	(573)
Deferred Federal Income Tax Expense (Benefit)	431	165	(76)
Deferred foreign	(8)	(20)	2
Deferred State and Local Income Tax Expense (Benefit)	(127)	(131)	100
Deferred Income Tax Expense (Benefit)	296	14	26
Other Tax Expense (Benefit)	(6)	(6)	(7)
Total income tax expense (benefit)	$ (598)	$ (583)	$ (554)