Stockholders' Equity - Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 2,708	$ 2,185
Other comprehensive (loss)/income, net of tax	(55)	31
Ending balance	2,753	2,317
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(726)	(629)
Other comprehensive (loss)/income, net of tax	(55)	31
Ending balance	(781)	(598)
Derivatives Net Unrealized Gains/ (Losses)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	0	(4)
Other comprehensive (loss)/income, net of tax	(28)	0
Ending balance	(28)	(4)
Net Investment Hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	21	10
Other comprehensive (loss)/income, net of tax	17	8
Ending balance	38	18
Currency Translation Adjustment Net Unrealized Gain/(Losses)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(724)	(621)
Other comprehensive (loss)/income, net of tax	(44)	23
Ending balance	(768)	(598)
Benefit Plans Actuarial Gains/(Losses)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(23)	(14)
Other comprehensive (loss)/income, net of tax	0	0
Ending balance	$ (23)	$ (14)