Income Taxes - Schedule of Breakdown of Income Tax Expense Between Current and Deferred (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ 608	$ 572	$ 787
State	104	144	117
Subtotal Current	712	716	904
Deferred:
Federal	235	275	(3,277)
State	38	4	44
Subtotal Deferred	273	279	(3,233)
Income Tax Expense	$ 985	$ 995	$ (2,329)