Derivatives and Hedging - Schedule of Derivative Gains (Losses) Recognized in the Consolidated Financial Statements (Details) - Foreign exchange contracts - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative [Line Items]
Gain (Loss) recognized in Accumulated other comprehensive loss	$ 5	$ (6)	$ (8)	$ (14)
Derivative gains (losses) reclassified from accumulated other comprehensive loss	(2)	(4)	(13)	(12)
Total revenue
Derivative [Line Items]
Derivative gains (losses) reclassified from accumulated other comprehensive loss	(3)	(4)	(12)	(11)
Compensation and benefits
Derivative [Line Items]
Derivative gains (losses) reclassified from accumulated other comprehensive loss	1	0	0	0
Interest expense
Derivative [Line Items]
Derivative gains (losses) reclassified from accumulated other comprehensive loss	$ 0	$ 0	$ (1)	$ (1)