Document and Entity Information
| Document and Entity Information | Sep. 22, 2022 |
| Cover [Abstract] | |
| Entity Registrant Name | ATI INC |
| Amendment Flag | true |
| Entity Central Index Key | 0001018963 |
| Document Type | 8-K/A |
| Document Period End Date | Sep. 22, 2022 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 1-12001 |
| Entity Tax Identification Number | 25-1792394 |
| Entity Address, Address Line One | 2021 McKinney Avenue |
| Entity Address, City or Town | Dallas |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 75201 |
| City Area Code | (412) |
| Local Phone Number | 394-2800 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, par value $0.10 per share |
| Trading Symbol | ATI |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Amendment Description | (b) On September 22, 2022, ATI Inc. (the “Company”) announced that Kevin B. Kramer, the Company’s Senior Vice President, Chief Commercial and Marketing Officer, will retire from the Company effective as of January 31, 2024. From January 1, 2023 through the effective time of his retirement, Mr. Kramer will serve as Senior Advisor to the Company’s Board Chair, President and Chief Executive Officer. (e) In connection with Mr. Kramer’s anticipated retirement, he and the Company entered into a Retirement, Transition and Release Agreement, dated as of October 12, 2022 (the “Retirement Agreement”), pursuant to which Mr. Kramer is entitled to certain benefits as more fully described in the Retirement Agreement. The Retirement Agreement, which is filed as Exhibit 10.1 to this Current Report on Form 8-K and incorporated herein by reference, also contains provisions that restrict Mr. Kramer from competing against the Company or soliciting employees or customers of the Company for a period of 24 months following the effective date of his retirement, together with other affirmative and negative covenants that are customary for agreements of this nature. |