| Document and Entity Information | Feb. 17, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | Allison Transmission Holdings Inc |
| Amendment Flag | false |
| Entity Central Index Key | 0001411207 |
| Document Type | 8-K |
| Document Period End Date | Feb. 17, 2021 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-35456 |
| 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 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common stock, $0.01 par value |
| Trading Symbol | ALSN |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
