v3.25.2
Document and Entity Information - shares
 6 Months Ended
Jun. 30, 2025
Jul. 22, 2025
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Document Transition Report false  
Document Period End Date Jun. 30, 2025  
Entity File Number 001-35456  
Entity Registrant Name ALLISON TRANSMISSION HOLDINGS, INC.  
Entity Incorporation, State or Country Code DE  
Entity Tax Identification Number 26-0414014  
Entity Address, Address Line One One Allison Way  
Entity Address, City or Town Indianapolis  
Entity Address, State or Province IN  
Entity Address, Postal Zip Code 46222  
City Area Code 317  
Local Phone Number 242-5000  
Title of 12(b) Security Common Stock, $0.01 par value  
Trading Symbol ALSN  
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  
Entity Common Stock, Shares Outstanding   83,616,722
Entity Central Index Key 0001411207  
Current Fiscal Year End Date --12-31  
Amendment Flag false  
Document Fiscal Year Focus 2025  
Document Fiscal Period Focus Q2