Derivatives and Hedging - Schedule of Derivative Gains (Losses) Recognized in the Consolidated Financial Statements (Details) - Foreign exchange contracts - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative [Line Items]
Loss recognized in Accumulated other comprehensive loss	$ (2)	$ (12)	$ (13)	$ (8)
Derivative gains (losses) reclassified from accumulated other comprehensive loss	(6)	(3)	(11)	(8)
Total revenue
Derivative [Line Items]
Derivative gains (losses) reclassified from accumulated other comprehensive loss	(5)	(3)	(9)	(7)
Compensation and benefits
Derivative [Line Items]
Derivative gains (losses) reclassified from accumulated other comprehensive loss	(1)	0	(1)	0
Interest expense
Derivative [Line Items]
Derivative gains (losses) reclassified from accumulated other comprehensive loss	$ 0	$ 0	$ (1)	$ (1)