Income Taxes - Schedule of Components of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ 229	$ (14)	$ 52
State	18	30	92
Non-U.S.	380	320	342
Total current expense	627	336	486
Deferred:
Federal	49	(311)	(39)
State	65	38	40
Non-U.S.	(19)	(85)	(169)
Total deferred expense (benefit)	95	(358)	(168)
Total income tax expense (benefit)	$ 722	$ (22)	$ 318