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REVENUES - Revenues By Product Line (Details) T in Thousands, $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2021 USD ($) T | Jun. 30, 2020 USD ($) T | Jun. 30, 2021 USD ($) T | Jun. 30, 2020 USD ($) T
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 5,045 | $ 1,093 | $ 9,094 | $ 1,452
Steelmaking |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 4,922 | 1,023 | 8,841 | 1,360
Other Businesses |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | 123 | 70 | 253 | 92
Hot-rolled steel | Steelmaking |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 1,485 | $ 42 | $ 2,404 | $ 61
Sales Volume (Net Tons) | T | 1,386 | 63 | 2,568 | 94
Cold-rolled steel | Steelmaking |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 773 | $ 88 | $ 1,417 | $ 116
Sales Volume (Net Tons) | T | 720 | 123 | 1,468 | 163
Coated steel | Steelmaking |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 1,379 | $ 301 | $ 2,703 | $ 391
Sales Volume (Net Tons) | T | 1,247 | 333 | 2,616 | 432
Stainless and electrical steel | Steelmaking |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 397 | $ 208 | $ 760 | $ 264
Sales Volume (Net Tons) | T | 168 | 95 | 335 | 122
Plate steel | Steelmaking |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 321 | $ 0 | $ 572 | $ 0
Sales Volume (Net Tons) | T | 273 | 0 | 548 | 0
Other steel products | Steelmaking |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 345 | $ 0 | $ 635 | $ 0
Sales Volume (Net Tons) | T | 411 | 0 | 814 | 0
Iron products | Steelmaking |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 155 | $ 377 | $ 225 | $ 519
Sales Volume (Long Tons) | T | 849 | 3,718 | 1,449 | 5,069
Other | Steelmaking |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 67 | $ 7 | $ 125 | $ 9
Other | Other Businesses |  |  |  |
Disaggregation of Revenue [Line Items] |  |  |  |
Revenues | $ 123 | $ 70 | $ 253 | $ 92

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