Other Financial Data - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Other Financial Data [Line Items]
Contract with customer, liability, revenue recognized			$ 94
Deferred consideration payments, Paid	$ 81		81
Alight Holdings
Other Financial Data [Line Items]
Contract with customer, liability, revenue recognized				$ 101
Deferred consideration payments, Paid				1
Interest Rate Swaps
Other Financial Data [Line Items]
Derivative asset, current	39		39		$ 1
Derivative asset, noncurrent	57		57		16
Derivative liability, current					8
Derivative liability, noncurrent					1
Other Current Liabilities
Other Financial Data [Line Items]
Tax receivable agreement liability	7		7
Deferred compensation liability					$ 83
Cost of Services, Exclusive of Depreciation and Amortization
Other Financial Data [Line Items]
Amortization expense	$ 13		$ 25
Cost of Services, Exclusive of Depreciation and Amortization | Alight Holdings
Other Financial Data [Line Items]
Amortization expense		$ 17		$ 33