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, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Derivative [Line Items]
Interest expense	$ 85	$ 74	$ 259	$ 204
(Gain) loss reclassified from AOCI	122	9	165	3
Cost of services
Derivative [Line Items]
Cost of revenue	925	957	2,864	2,902
Interest expense
Derivative [Line Items]
(Gain) loss reclassified from AOCI			18
Foreign exchange contracts | Other income (expense), net
Derivative [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	(3)	(2)	(11)	(20)
Interest rate contracts | Cost of services | Cash Flow Hedging
Derivative [Line Items]
(Gain) loss reclassified from AOCI	(100)	(4)	(134)	2
Interest rate contracts | Cost of services | Cost of services
Derivative [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	5	0	19	0
Interest rate contracts | Interest expense | Cash Flow Hedging
Derivative [Line Items]
(Gain) loss reclassified from AOCI	$ (22)	$ (5)	$ (31)	$ (5)