| Cover | Dec. 23, 2024 |
| Entity Addresses [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 23, 2024 |
| Entity File Number | 001-38694 |
| Entity Registrant Name | ARCADIUM LITHIUM PLC |
| Entity Central Index Key | 0001977303 |
| Entity Tax Identification Number | 98-1737136 |
| Entity Incorporation, State or Country Code | Y9 |
| Entity Address, Address Line One | 1818 Market Street |
| Entity Address, Address Line Two | Suite 2550 |
| Entity Address, City or Town | Philadelphia |
| Entity Address, State or Province | PA |
| Entity Address, Country | US |
| Entity Address, Postal Zip Code | 19103 |
| City Area Code | 215 |
| Local Phone Number | 299-5900 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Ordinary Shares, par value $1.00 per share |
| Trading Symbol | ALTM |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Other Address [Member] | |
| Entity Addresses [Line Items] | |
| Entity Address, Address Line One | Suite 12, Gateway Hub |
| Entity Address, Address Line Two | Shannon Airport House |
| Entity Address, City or Town | Shannon, Co. Clare |
| Entity Address, Country | IE |
| Entity Address, Postal Zip Code | V14 E370 |
| City Area Code | 353-1 |
| Local Phone Number | 6875238 |
