Derivatives and Hedging Instruments - Gain (Loss) on Derivatives (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022
Derivative Instruments, Gain (Loss) [Line Items]
(Gain) loss reclassified from AOCI	$ 19	$ (1)
Interest rate contracts \| Cash Flow Hedging \| Cost of services
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized	(11)	32
(Gain) loss reclassified from AOCI	(15)	1
Interest rate contracts \| Cash Flow Hedging \| Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized	0	25
(Gain) loss reclassified from AOCI	$ (4)	$ 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI https://asc.fasb.org/extlink&oid=126968391&loc=d3e689-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI https://asc.fasb.org/extlink&oid=126968391&loc=d3e637-108580

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=125515794&loc=SL5624171-113959

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration