Fair Value Measurement - Summary of Changes in Deferred Contingent Consideration Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2022
Business Acquisition, Contingent Consideration [Line Items]
Beginning balance	$ 25	$ 29		$ 33
Measurement period adjustments				(2)
Accretion of contingent consideration				1
Remeasurement of acquisition-related contingent consideration	(2)	0		(9)
Ending Balance	$ 23	29	$ 29	$ 23
Alight Holdings
Business Acquisition, Contingent Consideration [Line Items]
Beginning balance		$ 29	26
Measurement period adjustments			2
Accretion of contingent consideration			1
Ending Balance			$ 29