Stockholders' Equity - Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 2,753	$ 2,317	$ 2,708	$ 2,185
Other comprehensive (loss)/income, net of tax	(75)	(71)	(130)	(40)
Ending balance	2,987	2,411	2,987	2,411
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(781)	(598)	(726)	(629)
Other comprehensive (loss)/income, net of tax	(75)	(71)	(130)	(40)
Ending balance	(856)	(669)	(856)	(669)
Derivatives Net Unrealized Gains/ (Losses)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			0	(4)
Other comprehensive (loss)/income, net of tax			(32)	1
Ending balance	(32)	(3)	(32)	(3)
Net Investment Hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance			21	10
Other comprehensive (loss)/income, net of tax			3	4
Ending balance	24	14	24	14
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			(101)	(45)
Ending balance	(825)	(666)	(825)	(666)
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)	$ (23)	$ (14)