Earnings Per Share - Summary of Basic and Diluted Earnings Per Share (Details)
$ / shares in Units, $ in Millions
6 Months Ended
Dec. 31, 2021
USD ($)
$ / shares
shares
Numerator  
Net loss attributable to Alight, Inc. - basic and diluted | $ $ (35)
Denominator  
Weighted average shares outstanding - basic and diluted | shares 439,800,624
Basic and diluted net loss per share | $ / shares $ (0.08)