Income Taxes - Income Tax Provision (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current tax benefit (provision):
Federal	$ 94	$ 187	$ (4)
State and local	(39)	(26)	5
International	(13)	(13)	(54)
Deferred tax provision:
Federal	(1,343)	(1,226)	(2,093)
State and local	(130)	(138)	(149)
Income tax provision	$ (1,431)	$ (1,216)	$ (2,295)