Stockholders' Equity - Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 2,987	$ 2,411	$ 2,708	$ 2,185
Other comprehensive (loss)/income, net of tax	121	(30)	(9)	(70)
Ending balance	3,607	2,678	3,607	2,678
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(856)	(669)	(726)	(629)
Other comprehensive (loss)/income, net of tax	121	(30)	(9)	(70)
Ending balance	(735)	(699)	(735)	(699)
Derivatives Net Unrealized Gains/ (Losses)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			0	(4)
Other comprehensive (loss)/income, net of tax			(27)	(3)
Ending balance	(27)	(7)	(27)	(7)
Net Investment Hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			21	10
Other comprehensive (loss)/income, net of tax			(27)	28
Ending balance	(6)	38	(6)	38
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			46	(95)
Ending balance	(678)	(716)	(678)	(716)
Benefit Plans Actuarial Gains/(Losses)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			(23)	(14)
Other comprehensive (loss)/income, net of tax			(1)	0
Ending balance	$ (24)	$ (14)	$ (24)	$ (14)