Stockholders' and Members' Equity - Additional Information (Details) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022 Vote $ / shares shares	Mar. 31, 2022 shares	Jun. 30, 2022 USD ($) Vote $ / shares shares	Jun. 30, 2021 shares	Dec. 31, 2021 shares	Jul. 02, 2021 shares
Class Of Stock [Line Items]
Preferred stock, authorized	1,000,000		1,000,000
Preferred stock, par value | $ / shares	$ 0.0001		$ 0.0001
Preferred stock, issued	0		0
Preferred stock, outstanding	0		0
Increase in equity | $			$ 16
Tax Receivable Agreement Liability
Class Of Stock [Line Items]
Additional TRA liabilities | $			$ 7
Class A Common Stock
Class Of Stock [Line Items]
Common stock, shares issued	465,629,457		465,629,457
Common stock, shares outstanding	465,629,457		465,629,457
Common stock, par value | $ / shares	$ 0.0001		$ 0.0001
Common stock, shares authorized	1,000,000,000		1,000,000,000
Conversion of stock			1,572,971
Unvested Class A common stock
Class Of Stock [Line Items]
Common stock, shares issued	7,583,284		7,583,284
Common stock, shares outstanding	7,583,284		7,583,284
Class B Common Stock
Class Of Stock [Line Items]
Common stock, shares issued	9,980,906		9,980,906
Common stock, shares outstanding	9,980,906		9,980,906
Common stock, par value | $ / shares	$ 0.0001		$ 0.0001
Issuance of common units			14,999,998
Common stock, shares authorized	20,000,000		20,000,000
Unvested Common Class B
Class Of Stock [Line Items]
Issuance of employee compensation			808,276
Class B-1 Common Stock
Class Of Stock [Line Items]
Common stock, shares issued	4,990,453		4,990,453
Common stock, shares outstanding	4,990,453		4,990,453
Common stock shares related to employee compensation, unvested	404,138		404,138
Common stock conversion, description			Class B-1 Common Stock vest and automatically convert into shares of Class A Common Stock on a 1-for-1 basis if the volume weighted average price (“VWAP”) of the shares of Class A Common Stock equals or exceeds $12.50 per share for 20 or more trading days within a consecutive 30-trading day period (or in the event of a change of control or liquidation event that implies a $12.50 per share valuation on a diluted basis).
Common stock shares conversion ratio			1
Common stock shares convertible stock price trigger | $ / shares			$ 12.50
Common stock shares convertible threshold trading days			20 days
Common stock shares convertible threshold consecutive trading days			30 days
Common stock shares convertible stock valuation price on diluted basis | $ / shares			$ 12.50
Class B-1 Common Shares | Alight Holdings
Class Of Stock [Line Items]
Common stock, shares issued	2,509,546		2,509,546
Common stock, shares outstanding	2,509,546		2,509,546
Common stock conversion, description			Class B-1 common units vest and automatically convert into Class A common units of Alight Holdings on a 1-for-1 basis if the VWAP of the shares of Class A Common Stock equals or exceeds $12.50 per share for 20 or more trading days within a consecutive 30-trading day period (or in the event of a change of control or liquidation event that implies a $12.50 per share valuation on a diluted basis).
Common stock shares conversion ratio			1
Common stock shares convertible stock price trigger | $ / shares			$ 12.50
Common stock shares convertible threshold trading days			20 days
Common stock shares convertible threshold consecutive trading days			30 days
Common stock shares convertible stock valuation price on diluted basis | $ / shares			$ 12.50
Class B-2 Common Stock
Class Of Stock [Line Items]
Common stock, shares issued	4,990,453		4,990,453
Common stock, shares outstanding	4,990,453		4,990,453
Common stock shares related to employee compensation, unvested	404,138		404,138
Common stock conversion, description			Class B-2 Common Stock vest and automatically convert into shares of Class A Common Stock on a 1-for-1 basis if the VWAP of the shares of Class A Common Stock equals or exceeds $15.00 per share for 20 or more trading days within a consecutive 30-trading day period (or in the event of a change of control or liquidation event that implies a $15.00 per share valuation on a diluted basis).
Common stock shares conversion ratio			1
Common stock shares convertible stock price trigger | $ / shares			$ 15.00
Common stock shares convertible threshold trading days			20 days
Common stock shares convertible threshold consecutive trading days			30 days
Common stock shares convertible stock valuation price on diluted basis | $ / shares			$ 15.00
Class B-2 Common Units | Alight Holdings
Class Of Stock [Line Items]
Common stock, shares issued	2,509,546		2,509,546
Common stock, shares outstanding	2,509,546		2,509,546
Common stock conversion, description			Class B-2 common units vest and automatically convert into Class A common units of Alight Holdings on a 1-for-1 basis if the VWAP of the shares of Class A Common Stock equals or exceeds $15.00 per share for 20 or more trading days within a consecutive 30-trading day period (or in the event of a change of control or liquidation event that implies a $15.00 per share valuation on a diluted basis).
Common stock shares conversion ratio			1
Common stock shares convertible stock price trigger | $ / shares			$ 15.00
Common stock shares convertible threshold trading days			20 days
Common stock shares convertible threshold consecutive trading days			30 days
Common stock shares convertible stock valuation price on diluted basis | $ / shares			$ 15.00
Class B-3 Common Stock
Class Of Stock [Line Items]
Common stock, shares issued	0		0
Common stock, shares outstanding	0		0
Common stock, par value | $ / shares	$ 0.0001		$ 0.0001
Common stock, shares authorized	10,000,000		10,000,000
Class V Common Stock
Class Of Stock [Line Items]
Common stock, shares issued	75,886,716		75,886,716
Common stock, shares outstanding	75,886,716		75,886,716
Common stock, par value | $ / shares	$ 0.0001		$ 0.0001
Common stock shares conversion ratio			1
Common stock, shares authorized	175,000,000		175,000,000
Common shares, votes per share | Vote	1		1
Shares, outstanding	75,886,716	76,220,431	75,886,716		77,459,687
Conversion of stock	(333,715)	(1,239,256)
Class Z Common Stock
Class Of Stock [Line Items]
Common stock, shares issued	5,595,577		5,595,577			8,671,507
Common stock, shares outstanding	5,595,577		5,595,577
Common stock, par value | $ / shares	$ 0.0001		$ 0.0001
Common stock, shares authorized	12,900,000		12,900,000
Shares, outstanding	5,595,577	5,595,577	5,595,577		5,595,577
Class Z-A Common Stock
Class Of Stock [Line Items]
Common stock, shares issued	5,046,819		5,046,819
Common stock, shares outstanding	5,046,819		5,046,819
Class Z-B-1 Common Stock
Class Of Stock [Line Items]
Common stock, shares issued	274,379		274,379
Common stock, shares outstanding	274,379		274,379
Class Z-B-2 Common Stock
Class Of Stock [Line Items]
Common stock, shares issued	274,379		274,379
Common stock, shares outstanding	274,379		274,379
Class Z Common Units
Class Of Stock [Line Items]
Common stock, shares issued	3,075,930		3,075,930
Common stock, shares outstanding	3,075,930		3,075,930
Class Z-A Common Units
Class Of Stock [Line Items]
Common stock, shares issued	2,774,272		2,774,272
Common stock, shares outstanding	2,774,272		2,774,272
Class Z-B-1 Common Units
Class Of Stock [Line Items]
Common stock, shares issued	150,829		150,829
Common stock, shares outstanding	150,829		150,829
Class Z-B-2 Common Units
Class Of Stock [Line Items]
Common stock, shares issued	150,829		150,829
Common stock, shares outstanding	150,829		150,829
Class A Units
Class Of Stock [Line Items]
Common stock, shares outstanding	541,516,173		541,516,173
Shares, outstanding	465,629,457		465,629,457
Held by non controlling interest			75,886,716
Common Class A
Class Of Stock [Line Items]
Common units/stock voting rights			Each holder of Class A common units is entitled to one vote per unit.
Common Class A | Alight Holdings
Class Of Stock [Line Items]
Common units granted				0
Common Class A-1 Units
Class Of Stock [Line Items]
Common units/stock voting rights			Holders of Class A-1 common units are not entitled to voting rights.
Common Class A-1 Units | Alight Holdings
Class Of Stock [Line Items]
Common units granted				643
Common Class B Units
Class Of Stock [Line Items]
Common units/stock voting rights			Holders of Class B common units are not entitled to voting rights.
Common Class B Units | Alight Holdings
Class Of Stock [Line Items]
Common units granted				0