CAPITAL STOCK - Narrative (Details) - USD ($) $ / shares in Units, $ in Millions |
3 Months Ended | 12 Months Ended | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Dec. 01, 2021 |
Mar. 11, 2021 |
Dec. 09, 2020 |
Sep. 30, 2021 |
Dec. 31, 2023 |
Dec. 31, 2022 |
Dec. 31, 2021 |
Feb. 10, 2022 |
Apr. 29, 2021 |
Mar. 31, 2021 |
Feb. 11, 2021 |
Dec. 31, 2020 |
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| Class of Stock [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Authorized amount of stock repurchase | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | $ 1,000 | Ìý | Ìý | Ìý | Ìý |
| Repurchase of common shares | Ìý | Ìý | Ìý | Ìý | $ 152 | $ 240 | $ 0 | Ìý | Ìý | Ìý | Ìý | Ìý |
| Remaining authorized purchase amount | Ìý | Ìý | Ìý | Ìý | $ 608 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| 1.500% 2025 Convertible Senior Notes redemption | Ìý | Ìý | Ìý | Ìý | Ìý | $ (25) | $ (5) | Ìý | Ìý | Ìý | Ìý | Ìý |
| Common shares, issued (in shares) | Ìý | Ìý | Ìý | Ìý | 531,051,530 | 531,051,530 | Ìý | Ìý | Ìý | Ìý | 20,000,000 | Ìý |
| Common shares, sold (in shares) | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | 40,000,000 | Ìý |
| Common stock, shares issued, price per share (in usd per share) | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | $ 16.12 | Ìý |
| Redeemable preferred stock, issued (in shares) | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | 583,273 |
| Redeemable preferred stock, outstanding (in shares) | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | 583,273 |
| Common shares, authorized (in shares) | Ìý | Ìý | Ìý | Ìý | 1,200,000,000 | 1,200,000,000 | Ìý | Ìý | 1,200,000,000 | 600,000,000 | Ìý | Ìý |
| Common Stock | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Class of Stock [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Common stock repurchases (in shares) | Ìý | Ìý | Ìý | Ìý | 10,400,000 | 12,500,000 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| 1.500% 2025 Convertible Senior Notes redemption (in shares) | Ìý | Ìý | Ìý | Ìý | Ìý | 24,200,000 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Common Shares in Treasury | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Class of Stock [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Repurchase of common shares | Ìý | Ìý | Ìý | Ìý | $ 152 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| 1.500% 2025 Convertible Senior Notes | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Class of Stock [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Redemption of debt | $ 294 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Repayments of debt | 294 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| 1.500% 2025 Convertible Senior Notes redemption | $ 499 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| 9.875% 2025 Senior Secured Notes | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Class of Stock [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Redemption of debt | Ìý | $ 322 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| ArcelorMittal | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Class of Stock [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Common shares, sold (in shares) | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | 40,000,000 | Ìý |
| Common Stock | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Class of Stock [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| 1.500% 2025 Convertible Senior Notes redemption (in shares) | 24,000,000 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Common Stock | ArcelorMittal USA | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Class of Stock [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Acquisition (in shares) | Ìý | Ìý | 78,000,000 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Series B Preferred Stock | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Class of Stock [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Stock redeemed during period (in shares) | Ìý | Ìý | Ìý | 583,273 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Stock redeemed during period | Ìý | Ìý | Ìý | $ 1,300 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Preferred stock authorized (in shares) | Ìý | Ìý | Ìý | Ìý | 4,000,000 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Preferred stock issued (in shares) | Ìý | Ìý | Ìý | Ìý | 0 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Preferred stock outstanding (in shares) | Ìý | Ìý | Ìý | Ìý | 0 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Series A Preferred Stock | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Class of Stock [Line Items] | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Preferred stock authorized (in shares) | Ìý | Ìý | Ìý | Ìý | 3,000,000 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Preferred stock issued (in shares) | Ìý | Ìý | Ìý | Ìý | 0 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
| Preferred stock outstanding (in shares) | Ìý | Ìý | Ìý | Ìý | 0 | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý | Ìý |
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- Definition Common Stock, Shares, Sold No definition available.
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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. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Gross amount of debt extinguished. No definition available.
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- Definition The cash outflow to reacquire common stock during the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The maximum number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) permitted to be issued by an entity's charter and bylaws. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of cash outflow for short-term and long-term debt. Excludes payment of lease obligation. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Per share or per unit amount of equity securities issued. No definition available.
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- Definition Number of shares of stock issued during the period pursuant to acquisitions. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Number of shares issued during the period as a result of the conversion of convertible securities. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The net amount of stock issued during the period upon the conversion of convertible securities, net of adjustments (for example, to additional paid in capital) including the write-off of an equity component recognized to record the convertible debt instrument as two separate components - a debt component and an equity component. This item is meant to disclose the value of shares issued on conversion of convertible securities that were recorded as two separate (debt and equity) components. No definition available.
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- Definition Number of stock bought back by the entity at the exercise price or redemption price. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Equity impact of the value of stock bought back by the entity at the exercise price or redemption price. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition Amount of stock repurchase plan authorized. No definition available.
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- Definition Amount remaining of a stock repurchase plan authorized. No definition available.
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- Definition Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The number of securities classified as temporary equity that have been sold (or granted) to the entity's shareholders. Securities issued include securities outstanding and securities held in treasury. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition The number of securities classified as temporary equity that have been issued and are held by the entity's shareholders. Securities outstanding equals securities issued minus securities held in treasury. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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