Derivatives and Hedging Instruments - Gain (Loss) on Derivatives (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Derivative Instruments, Gain (Loss) [Line Items]
(Gain) loss reclassified from AOCI	$ 122	$ 9	$ 165	$ 3
Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
(Gain) loss reclassified from AOCI			18
Interest rate contracts | Cash Flow Hedging | Cost of services
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized	0	77	24	119
(Gain) loss reclassified from AOCI	(100)	(4)	(134)	2
Interest rate contracts | Cash Flow Hedging | Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized	0	0	0	36
(Gain) loss reclassified from AOCI	$ (22)	$ (5)	$ (31)	$ (5)