Accounting Policies and Practices - Additional Information (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies And Practices [Line Items]
Cash and cash equivalents	$ 372		$ 358	$ 250
Allowance for expected credit losses			12	9
Foreign exchange gains (losses)			$ (10)	1
Minimum percentage of unrecognized tax benefit likely to be realized			50.00%
Fiduciary assets			$ 1,401	$ 1,509
Alight Holdings
Accounting Policies And Practices [Line Items]
Cash and cash equivalents		$ 460
Foreign exchange gains (losses)	$ (4)	$ (9)