Accumulated Other Comprehensive Loss - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Estimate of losses related to foreign currency exchange contracts during the next 12 months		$ 6
Fair market value adjustment on cash flow hedges, net of income tax benefit of $3 million and $8 million	$ 183	(8)	$ (23)
Estimated interest expense related to settled interest rate hedge contracts during the next twelve months		21
Foreign currency translation adjustment		55
Foreign currency forward exchange contracts | Indian Rupee
Accumulated Other Comprehensive Income (Loss) [Line Items]
Notional amount of derivatives		227		$ 178
Total fair value of cash flow hedge derivatives		$ 8		$ 4
Treasury Lock
Accumulated Other Comprehensive Income (Loss) [Line Items]
Derivative liability, notional amount			$ 5,000