Derivatives and Hedging Instruments - Gain (Loss) on Derivatives Not Designated as Hedging Instruments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Derivative [Line Items]
Interest expense	$ 40	$ 83	$ 120	$ 257
(Gain) loss reclassified from AOCI	0	122	0	165
Cost of services
Derivative [Line Items]
Cost of revenue	360	361	1,120	1,053
Foreign exchange contracts | Other income (expense), net
Derivative [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	(2)	(3)	(8)	(8)
Interest rate contracts | Cost of services | Cash Flow Hedging
Derivative [Line Items]
(Gain) loss reclassified from AOCI	0	(100)	0	(134)
Interest rate contracts | Interest expense | Cash Flow Hedging
Derivative [Line Items]
(Gain) loss reclassified from AOCI	0	(22)	0	(31)
Interest rate contracts | Cost of services | Cost of services
Derivative [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$ 0	$ 14	$ 0	$ 14