Segment Reporting - Schedule of Current Reportable and Recast of Segments by Revenue (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Segment Reporting Information [Line Items]
Revenue	$ 559	$ 586
Other
Segment Reporting Information [Line Items]
Revenue		10
Operating Segments \| Employer Solutions
Segment Reporting Information [Line Items]
Revenue	559	576
Operating Segments \| Employer Solutions \| Recurring
Segment Reporting Information [Line Items]
Revenue	521	533
Operating Segments \| Employer Solutions \| Project
Segment Reporting Information [Line Items]
Revenue	$ 38	$ 43

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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Reference 5: http://www.xbrl.org/2003/role/disclosureRef
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Reference 6: http://www.xbrl.org/2003/role/disclosureRef
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+ Details