v3.24.3
Cover - shares
 9 Months Ended
Sep. 30, 2024
Nov. 07, 2024
Document Information [Line Items]    
Document Type 10-Q  
Document Quarterly Report true  
Document Period End Date Sep. 30, 2024  
Document Transition Report false  
Entity File Number 001-39299  
Entity Registrant Name Alight, Inc. / Delaware  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 86-1849232  
Entity Address, Address Line One 320 South Canal Street,  
Entity Address, Address Line Two 50th Floor, Suite 5000  
Entity Address, City or Town Chicago  
Entity Address, State or Province IL  
Entity Address, Postal Zip Code 60606  
City Area Code 224  
Local Phone Number 737-7000  
Title of 12(b) Security Class A Common Stock, par value $0.0001 per share  
Trading Symbol ALIT  
Security Exchange Name NYSE  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Amendment Flag false  
Document Fiscal Year Focus 2024  
Document Fiscal Period Focus Q3  
Entity Central Index Key 0001809104  
Current Fiscal Year End Date --12-31  
Class A Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   532,506,339
Class B-1 Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   4,978,807
Class B-2 Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   4,978,807
Class V Common Stock    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   560,433