| Document and Entity Information | Jul. 02, 2021 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Jul. 2,
2021 |
| Entity Registrant Name | ALIGHT GROUP, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-39299 |
| Entity Tax Identification Number | 85-0545098 |
| Entity Address, Address Line One | 4 Overlook Point |
| Entity Address, City or Town | Lincolnshire |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60069 |
| City Area Code | 224 |
| Local Phone Number | 737-7000 |
| Entity Information, Former Legal or Registered Name | Foley Trasimene Acquisition Corp. |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Current Fiscal Year End Date | --12-31 |
| Amendment Flag | false |
| Entity Central Index Key | 0001809104 |
| Former Address [Member] | |
| Document Information [Line Items] | |
| Entity Address, Address Line One | 1701 Village Center Circle |
| Entity Address, City or Town | Las Vegas |
| Entity Address, State or Province | NV |
| Entity Address, Postal Zip Code | 89134 |
| Class A common stock [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Class A common stock, par value $0.0001 per share |
| Trading Symbol | WPF |
| Security Exchange Name | NYSE |
| Units, each consisting of one share of Class A common stock and one-third of one redeemable warrant [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Units, each consisting of one share of Class A common stock and one-third of one Warrant |
| Trading Symbol | WPF.U |
| Security Exchange Name | NYSE |
| Warrants, each whole warrant exercisable for one share of Class A common stock at an exercise price of $11.50 per share [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Warrants, each whole warrant exercisable for one share of Class A common stock at an exercise price of $11.50 per share |
| Trading Symbol | WPF.WS |
| Security Exchange Name | NYSE |
