Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Foreign currency translation adjustments, income tax	$ (2)	$ (17)	$ (1)
Foreign currency, reclassification to earnings, income tax benefit (expense)	0	0	0
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	27	10	(7)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	(24)	(1)	(8)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Tax	1	(1)	(6)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	1	6	106
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax	$ (2)	$ (135)	$ (3)