Other Financial Data - Additional Information (Details) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2023	Dec. 31, 2022	Jul. 01, 2021
Other Financial Data [Line Items]
Allowance for expected credit losses			$ 12	$ 9
Fixed assets, net			371	320
Contract with customer, liability, revenue recognized			$ 163	$ 123
Operating lease expiration period			2031	2031
Alight Holdings
Other Financial Data [Line Items]
Business combination, fixed assets acquired, accumulated depreciation					$ 0
Contract with customer, liability, revenue recognized	$ 44	$ 101
Finance Leased Assets Included in Computer Equipment
Other Financial Data [Line Items]
Fixed assets, net			$ 21	$ 46
Interest Rate Swaps
Other Financial Data [Line Items]
Derivative asset, noncurrent			$ 17	$ 62
Derivative Asset, Noncurrent, Statement of Financial Position [Extensible Enumeration]			Other Assets, Noncurrent	Other Assets, Noncurrent
Derivative Asset, Current			$ 60	$ 72
Derivative Asset, Current, Statement of Financial Position [Extensible Enumeration]			Other Assets, Current	Other Assets, Current
Derivative liability, current			$ 0	$ 0
Derivative Liability, Current, Statement of Financial Position [Extensible Enumeration]			Other Liabilities, Current	Other Liabilities, Current
Derivative liability, noncurrent			$ 3	$ 0
Derivative Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]			Other Liabilities, Noncurrent	Other Liabilities, Noncurrent
Other Current Liabilities
Other Financial Data [Line Items]
Tax receivable agreement liability			$ 62	$ 7
Cost of Services, Exclusive of Depreciation and Amortization
Other Financial Data [Line Items]
Amortization expense			$ 56	$ 50
Cost of Services, Exclusive of Depreciation and Amortization | Alight Holdings
Other Financial Data [Line Items]
Amortization expense	$ 31	$ 33