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v3.21.2

Per Share Information (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2021 | Jun. 30, 2020 | Jun. 30, 2021 | Jun. 30, 2020 | Dec. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |  |  |
Net loss attributable to ATI | $ (49.2) | $ (422.6) | $ (57.1) | $ (401.5) |
Net loss attributable to ATI after assumed conversions | $ (49.2) | $ (422.6) | $ (57.1) | $ (401.5) |
Denominator for basic net loss per common share – weighted average shares | 127.1 | 126.6 | 127.0 | 126.4 |
Share-based compensation | 0.0 | 0.0 | 0.0 | 0.0 |
Denominator for diluted net loss per common share – adjusted weighted average shares and assumed conversions | 127.1 | 126.6 | 127.0 | 126.4 |
Basic net (loss) income attributable to ATI per common share (in dollars per share) | $ (0.39) | $ (3.34) | $ (0.45) | $ (3.18) |
Diluted net (loss) income attributable to ATI per common share (in dollars per share) | $ (0.39) | $ (3.34) | $ (0.45) | $ (3.18) |
Antidilutive Securities Excluded from Computation of Earnings Per Share Amount | 25.7 | 20.5 | 25.7 | 20.4 |
Allegheny Technologies 4.75% Convertible Senior Notes due 2022 |  |  |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |  |  |
Convertible Senior Notes- Effect on numerator | $ 0.0 | $ 0.0 | $ 0.0 | $ 0.0 |
Convertible Senior Notes- Effect on denominator | 0.0 | 0.0 | 0.0 | 0.0 |
Interest rate | 4.75% |  | 4.75% |  | 4.75%
Allegheny Technologies 3.5% Convertible Senior Notes due 2025 |  |  |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |  |  |
Convertible Senior Notes- Effect on numerator | $ 0.0 | $ 0.0 | $ 0.0 | $ 0.0 |
Convertible Senior Notes- Effect on denominator | 0.0 | 0.0 | 0.0 | 0.0 |

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