v3.21.2
Stockholders' and Members' Equity - Additional Information (Details)
 6 Months Ended 9 Months Ended
Jun. 30, 2021
shares
Sep. 30, 2021
Vote
$ / shares
shares
Sep. 30, 2020
shares
Dec. 31, 2020
shares
Class Of Stock [Line Items]        
Preferred stock, authorized   1,000,000    
Preferred stock, par value | $ / shares   $ 0.0001    
Preferred stock, issued   0    
Preferred stock, outstanding   0    
Class A Common Stock        
Class Of Stock [Line Items]        
Common stock, shares issued   446,802,741    
Common stock, shares outstanding   446,802,741    
Common stock, par value | $ / shares   $ 0.0001    
Common stock, shares authorized   1,000,000,000    
Unvested Class A common stock        
Class Of Stock [Line Items]        
Common stock, shares issued   7,821,091    
Common stock, shares outstanding   7,821,091    
Common stock, par value | $ / shares   $ 0.0001    
Class B Common Stock        
Class Of Stock [Line Items]        
Common stock, shares issued   9,980,906    
Common stock, shares outstanding   9,980,906    
Common stock, par value | $ / shares   $ 0.0001    
Issuance of common units   14,999,998    
Common stock, shares authorized   20,000,000    
Unvested Common Class B        
Class Of Stock [Line Items]        
Issuance of employee compensation   850,416    
Class B-1 Common Stock        
Class Of Stock [Line Items]        
Common stock, shares issued   4,990,453    
Common stock, shares outstanding   4,990,453    
Common stock, par value | $ / shares   $ 0.0001    
Common stock shares related to employee compensation, unvested   425,208    
Common stock conversion, description   Class B-1 common shares 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 Class A common shares 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    
Common stock, shares outstanding   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 Class A common shares 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    
Common stock, shares outstanding   4,990,453    
Common stock, par value | $ / shares   $ 0.0001    
Common stock shares related to employee compensation, unvested   425,208    
Common stock conversion, description   Class B-2 common shares vest and automatically convert into shares of Class A common shares on a 1-for-1 basis if the VWAP of the Class A common shares 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    
Common stock, shares outstanding   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 Class A common shares 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    
Common stock, shares outstanding   0    
Common stock, par value | $ / shares   $ 0.0001    
Common stock, shares authorized   10,000,000    
Class V Common Stock        
Class Of Stock [Line Items]        
Common stock, shares issued   77,459,687    
Common stock, shares outstanding   77,459,687    
Common stock, par value | $ / shares   $ 0.0001    
Common stock shares conversion ratio   1    
Common stock, shares authorized   175,000,000    
Common shares, votes per share | Vote   1    
Shares, outstanding 77,459,687 77,459,687    
Class Z Common Stock        
Class Of Stock [Line Items]        
Common stock, shares issued   5,595,577   8,671,507
Common stock, shares outstanding   5,595,577    
Common stock, par value | $ / shares   $ 0.0001    
Common stock, shares authorized   12,900,000    
Shares, outstanding 5,595,577 5,595,577    
Class Z-A Common Stock        
Class Of Stock [Line Items]        
Common stock, shares issued   5,046,819    
Common stock, shares outstanding   5,046,819    
Common stock, par value | $ / shares   $ 0.0001    
Class Z-B-1 Common Stock        
Class Of Stock [Line Items]        
Common stock, shares issued   274,379    
Common stock, shares outstanding   274,379    
Common stock, par value | $ / shares   $ 0.0001    
Class Z-B-2 Common Stock        
Class Of Stock [Line Items]        
Common stock, shares issued   274,379    
Common stock, shares outstanding   274,379    
Common stock, par value | $ / shares   $ 0.0001    
Class Z Common Units        
Class Of Stock [Line Items]        
Common stock, shares issued   3,075,930    
Common stock, shares outstanding   3,075,930    
Class Z-A Common Units        
Class Of Stock [Line Items]        
Common stock, shares issued   2,774,272    
Common stock, shares outstanding   2,774,272    
Class Z-B-1 Common Units        
Class Of Stock [Line Items]        
Common stock, shares issued   150,829    
Common stock, shares outstanding   150,829    
Class Z-B-2 Common Units        
Class Of Stock [Line Items]        
Common stock, shares issued   150,829    
Common stock, shares outstanding   150,829    
Class A Units        
Class Of Stock [Line Items]        
Common stock, shares outstanding   524,262,428    
Shares, outstanding   446,802,741    
Held by non controlling interest   77,459,687    
Common Class A Units        
Class Of Stock [Line Items]        
Common units granted 0   0  
Common units/stock voting rights   Each holder of Class A common units is entitled to one vote per unit.    
Common Class A-1 Units        
Class Of Stock [Line Items]        
Common units granted 643   0  
Common units/stock voting rights   Holders of Class A-1 common units are not entitled to voting rights.    
Common Class B Units        
Class Of Stock [Line Items]        
Common units granted 0   6,409  
Common units/stock voting rights   Holders of Class B common units are not entitled to voting rights.