Derivatives and Hedging Instruments - Gain (Loss) on Derivatives (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Derivative Instruments, Gain (Loss) [Line Items]
(Gain) loss reclassified from AOCI	$ 24	$ (5)	$ 43	$ (6)
Interest rate contracts \| Cash Flow Hedging \| Cost of services
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized	35	10	24	42
(Gain) loss reclassified from AOCI	(19)	5	(34)	6
Interest rate contracts \| Cash Flow Hedging \| Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized	0	11	0	36
(Gain) loss reclassified from AOCI	$ (5)	$ 0	$ (9)	$ 0

Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 11
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-11

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 220
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 15
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482790/220-10-45-15

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 4C
-Subparagraph (c)
-SubTopic 10
-Topic 815
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480434/815-10-50-4C

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration