Income Taxes - Schedule of Provision for Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components of Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal - Current	$ 1,716	$ 8,817	$ 3,351
Federal - Deferred	324	(123)	(85)
Federal Income Tax Expense (Benefit), Continuing Operations	2,040	8,694	3,266
State - Current	162	97	131
State - Deferred	(17)	(20)	28
State and Local Income Tax Expense (Benefit), Continuing Operations	145	77	159
Foreign - Current	175	54	261
Foreign - Deferred	(21)	60	(77)
Foreign Income Tax Expense (Benefit), Continuing Operations	154	114	184
Provision for Income Taxes	$ 2,339	$ 8,885	$ 3,609