Incomes Taxes (Income Tax (Benefit) Provision) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
United States, current federal tax expense (benefit)	$ (70)	$ 138	$ 34
Current foreign tax expense (benefit)	182	213	167
Current state and local tax expense (benefit)	12	12	7
Current income tax expense (benefit)	124	363	208
United States, deferred federal income tax expense (benefit)	120	386	120
Deferred foreign income tax expense (benefit)	(119)	(233)	(154)
Deferred state and local income tax expense (benefit)	13	34	12
Deferred income tax expense (benefit)	14	187	(22)
Total income tax expense	$ 138	$ 550	$ 186