GOODWILL AND INTANGIBLE ASSETS AND LIABILITIES - Goodwill (Details) - USD ($) $ in Millions |
12 Months Ended | ||
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Dec. 31, 2020 |
Mar. 13, 2020 |
Dec. 31, 2019 |
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Goodwill [Line Items] | Ìý | Ìý | Ìý |
Goodwill | $ 1,406 | Ìý | $ 2 |
ArcelorMittal USA [Member] | Ìý | Ìý | Ìý |
Goodwill [Line Items] | Ìý | Ìý | Ìý |
Goodwill | 1,230 | Ìý | Ìý |
AK Steel [Member] | Ìý | Ìý | Ìý |
Goodwill [Line Items] | Ìý | Ìý | Ìý |
Goodwill | 174 | $ 141 | Ìý |
Steelmaking [Member] | Ìý | Ìý | Ìý |
Goodwill [Line Items] | Ìý | Ìý | Ìý |
Goodwill | 1,232 | Ìý | 2 |
Steelmaking [Member] | ArcelorMittal USA [Member] | Ìý | Ìý | Ìý |
Goodwill [Line Items] | Ìý | Ìý | Ìý |
Goodwill, Period Increase (Decrease) | 1,230 | Ìý | Ìý |
Other businesses | Ìý | Ìý | Ìý |
Goodwill [Line Items] | Ìý | Ìý | Ìý |
Goodwill | 174 | Ìý | $ 0 |
Other businesses | AK Steel [Member] | Ìý | Ìý | Ìý |
Goodwill [Line Items] | Ìý | Ìý | Ìý |
Goodwill, Period Increase (Decrease) | $ 174 | Ìý | Ìý |
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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Amount of increase (decrease) of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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