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Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2023 | Sep. 30, 2022
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | $ 1,025.6 | $ 1,032.0 | $ 3,109.7 | $ 2,825.6
Percent of revenue | 100.00% | 100.00% | 100.00% | 100.00%
Nickel-based Alloys and Specialty Alloys [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 47.00% | 54.00% | 50.00% | 52.00%
Precision and Engineered Strip [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 9.00% | 12.00% | 9.00% | 14.00%
Precision Forgings, Casting and Components [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 18.00% | 15.00% | 17.00% | 15.00%
Titanium and Titanium-based Alloys [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 19.00% | 11.00% | 16.00% | 11.00%
Zirconium and Related Alloys [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 7.00% | 8.00% | 8.00% | 8.00%
UNITED STATES |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | $ 556.8 | $ 617.1 | $ 1,713.4 | $ 1,663.4
Asia [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 141.2 | 169.6 | 449.2 | 483.8
Europe [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 267.4 | 200.2 | 757.4 | 543.9
CANADA |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 23.5 | 19.5 | 76.6 | 62.9
South America, Middle East, and Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 36.7 | 25.6 | 113.1 | 71.6
Aerospace and Defense Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 625.8 | 530.1 | 1,808.3 | 1,333.3
Jet Engines- Commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 329.4 | 312.6 | 981.2 | 757.9
Airframes- Commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 203.6 | 131.4 | 537.7 | 331.2
Defense [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 92.8 | 86.1 | 289.4 | 244.2
Energy |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 148.9 | 192.7 | 538.6 | 552.7
Oil & Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 87.0 | 127.1 | 325.8 | 355.4
Specialty Energy [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 61.9 | 65.6 | 212.8 | 197.3
Automotive Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 48.1 | 69.6 | 160.3 | 236.1
Electronic Devices Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 44.8 | 48.5 | 115.2 | 149.5
Construction Mining Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 40.0 | 47.8 | 128.8 | 139.7
Food Equipment and Appliances Market |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 16.2 | 45.2 | 58.6 | 141.9
Medical Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 47.5 | 47.4 | 124.4 | 123.1
Other Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 54.3 | 50.7 | 175.5 | 149.3
Operating Segments |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 1,129.9 | 1,151.8 | 3,461.5 | 3,131.1
Operating Segments | High Performance Materials & Components |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | $ 578.1 | $ 505.0 | $ 1,670.5 | $ 1,325.6
Percent of revenue | 100.00% | 100.00% | 100.00% | 100.00%
Operating Segments | High Performance Materials & Components | Nickel-based Alloys and Specialty Alloys [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 42.00% | 52.00% | 45.00% | 50.00%
Operating Segments | High Performance Materials & Components | Precision and Engineered Strip [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 1.00% | 0.00% | 1.00% | 0.00%
Operating Segments | High Performance Materials & Components | Precision Forgings, Casting and Components [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 33.00% | 32.00% | 33.00% | 34.00%
Operating Segments | High Performance Materials & Components | Titanium and Titanium-based Alloys [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 24.00% | 16.00% | 21.00% | 16.00%
Operating Segments | High Performance Materials & Components | Zirconium and Related Alloys [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 0.00% | 0.00% | 0.00% | 0.00%
Operating Segments | High Performance Materials & Components | UNITED STATES |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | $ 242.6 | $ 221.6 | $ 661.1 | $ 557.8
Operating Segments | High Performance Materials & Components | Asia [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 37.8 | 60.7 | 132.8 | 155.4
Operating Segments | High Performance Materials & Components | Europe [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 217.7 | 147.0 | 619.7 | 403.3
Operating Segments | High Performance Materials & Components | CANADA |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 13.1 | 10.0 | 41.7 | 33.0
Operating Segments | High Performance Materials & Components | South America, Middle East, and Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 28.3 | 18.3 | 82.4 | 45.8
Operating Segments | High Performance Materials & Components | Aerospace and Defense Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 456.2 | 374.0 | 1,287.8 | 947.6
Operating Segments | High Performance Materials & Components | Jet Engines- Commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 312.5 | 285.7 | 914.2 | 696.1
Operating Segments | High Performance Materials & Components | Airframes- Commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 104.0 | 49.8 | 242.0 | 130.9
Operating Segments | High Performance Materials & Components | Defense [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 39.7 | 38.5 | 131.6 | 120.6
Operating Segments | High Performance Materials & Components | Energy |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 22.7 | 33.3 | 83.6 | 120.1
Operating Segments | High Performance Materials & Components | Oil & Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 2.5 | 6.9 | 8.6 | 32.1
Operating Segments | High Performance Materials & Components | Specialty Energy [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 20.2 | 26.4 | 75.0 | 88.0
Operating Segments | High Performance Materials & Components | Automotive Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 7.2 | 3.5 | 19.5 | 8.7
Operating Segments | High Performance Materials & Components | Electronic Devices Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 0.6 | 0.7 | 1.8 | 1.9
Operating Segments | High Performance Materials & Components | Construction Mining Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 7.7 | 9.5 | 26.9 | 25.8
Operating Segments | High Performance Materials & Components | Food Equipment and Appliances Market |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 0.0 | 0.2 | 0.0 | 0.2
Operating Segments | High Performance Materials & Components | Medical Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 28.9 | 22.3 | 70.7 | 52.3
Operating Segments | High Performance Materials & Components | Other Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 16.2 | 14.1 | 47.4 | 38.7
Operating Segments | Advanced Alloys & Solutions |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | $ 551.8 | $ 646.8 | $ 1,791.0 | $ 1,805.5
Percent of revenue | 100.00% | 100.00% | 100.00% | 100.00%
Operating Segments | Advanced Alloys & Solutions | Nickel-based Alloys and Specialty Alloys [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 52.00% | 57.00% | 56.00% | 55.00%
Operating Segments | Advanced Alloys & Solutions | Precision and Engineered Strip [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 19.00% | 22.00% | 18.00% | 25.00%
Operating Segments | Advanced Alloys & Solutions | Precision Forgings, Casting and Components [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 0.00% | 0.00% | 0.00% | 0.00%
Operating Segments | Advanced Alloys & Solutions | Titanium and Titanium-based Alloys [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 13.00% | 7.00% | 11.00% | 6.00%
Operating Segments | Advanced Alloys & Solutions | Zirconium and Related Alloys [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Percent of revenue | 16.00% | 14.00% | 15.00% | 14.00%
Operating Segments | Advanced Alloys & Solutions | UNITED STATES |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | $ 314.2 | $ 395.5 | $ 1,052.3 | $ 1,105.6
Operating Segments | Advanced Alloys & Solutions | Asia [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 103.4 | 108.9 | 316.4 | 328.4
Operating Segments | Advanced Alloys & Solutions | Europe [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 49.7 | 53.2 | 137.7 | 140.6
Operating Segments | Advanced Alloys & Solutions | CANADA |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 10.4 | 9.5 | 34.9 | 29.9
Operating Segments | Advanced Alloys & Solutions | South America, Middle East, and Other [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 8.4 | 7.3 | 30.7 | 25.8
Operating Segments | Advanced Alloys & Solutions | Aerospace and Defense Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 169.6 | 156.1 | 520.5 | 385.7
Operating Segments | Advanced Alloys & Solutions | Jet Engines- Commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 16.9 | 26.9 | 67.0 | 61.8
Operating Segments | Advanced Alloys & Solutions | Airframes- Commercial [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 99.6 | 81.6 | 295.7 | 200.3
Operating Segments | Advanced Alloys & Solutions | Defense [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 53.1 | 47.6 | 157.8 | 123.6
Operating Segments | Advanced Alloys & Solutions | Energy |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 126.2 | 159.4 | 455.0 | 432.6
Operating Segments | Advanced Alloys & Solutions | Oil & Gas [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 84.5 | 120.2 | 317.2 | 323.3
Operating Segments | Advanced Alloys & Solutions | Specialty Energy [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 41.7 | 39.2 | 137.8 | 109.3
Operating Segments | Advanced Alloys & Solutions | Automotive Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 40.9 | 66.1 | 140.8 | 227.4
Operating Segments | Advanced Alloys & Solutions | Electronic Devices Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 44.2 | 47.8 | 113.4 | 147.6
Operating Segments | Advanced Alloys & Solutions | Construction Mining Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 32.3 | 38.3 | 101.9 | 113.9
Operating Segments | Advanced Alloys & Solutions | Food Equipment and Appliances Market |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 16.2 | 45.0 | 58.6 | 141.7
Operating Segments | Advanced Alloys & Solutions | Medical Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 18.6 | 25.1 | 53.7 | 70.8
Operating Segments | Advanced Alloys & Solutions | Other Market [Member] |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 38.1 | 36.6 | 128.1 | 110.6
External Customers | Operating Segments |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 1,025.6 | 1,032.0 | 3,109.7 | 2,825.6
External Customers | Operating Segments | High Performance Materials & Components |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | 539.5 | 457.6 | 1,537.7 | 1,195.3
External Customers | Operating Segments | Advanced Alloys & Solutions |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenue | $ 486.1 | $ 574.4 | $ 1,572.0 | $ 1,630.3

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