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DEBT AND CREDIT FACILITIES - Schedule of Extinguishment of Debt (Details) - USD ($) $ in Millions |  |  |  |  | 3 Months Ended |  |
--- | --- | --- | --- | --- | --- | --- | ---
Mar. 12, 2021 | Mar. 11, 2021 | Mar. 27, 2020 | Mar. 13, 2020 | Mar. 31, 2021 | Mar. 31, 2020 | Feb. 11, 2021 | Dec. 31, 2020
Extinguishment of Debt [Line Items] |  |  |  |  |  |  |  |
Debt Extinguished |  |  |  |  | $ 857.0 | $ 740.0 |  |
Common shares, issued (in shares) |  |  |  |  | 506,832,537 |  | 20,000,000 | 506,832,537
(Loss) on Extinguishment |  |  |  |  | $ (66.0) | 3.0 |  |
9.875% 2025 Senior Secured Notes |  |  |  |  |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |  |  |  |  |
Debt Extinguished |  | $ 322.0 |  |  | 322.0 |  |  |
(Loss) on Extinguishment |  |  |  |  | (42.0) |  |  |
4.875% 2024 Senior Notes |  |  |  |  |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |  |  |  |  |
Debt Extinguished |  |  |  |  | 395.0 |  |  |
(Loss) on Extinguishment |  |  |  |  | (14.0) |  |  |
7.625% 2021 AK Senior Notes |  |  |  |  |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |  |  |  |  |
Debt Extinguished |  |  | $ 9.0 | $ 364.0 | 34.0 | 373.0 |  |
(Loss) on Extinguishment |  |  |  |  | 0.0 | 0.0 |  |
7.50% Senior Secured Notes due July 2023 |  |  |  |  |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |  |  |  |  |
Debt Extinguished |  |  | $ 56.0 | $ 311.0 | 13.0 | 367.0 |  |
(Loss) on Extinguishment |  |  |  |  | 0.0 | $ 3.0 |  |
6.375% 2025 Senior Notes |  |  |  |  |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |  |  |  |  |
Debt Extinguished |  |  |  |  | 64.0 |  |  |
(Loss) on Extinguishment |  |  |  |  | (7.0) |  |  |
6.375% 2025 AK Senior Notes |  |  |  |  |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |  |  |  |  |
Debt Extinguished |  |  |  |  | 29.0 |  |  |
(Loss) on Extinguishment |  |  |  |  | $ (3.0) |  |  |
Senior Notes |  |  |  |  |  |  |  |
Extinguishment of Debt [Line Items] |  |  |  |  |  |  |  |
Debt Extinguished | $ 535.0 |  |  |  |  |  |  |

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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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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