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v3.20.4

Other Events (Details) $ / shares in Units, t in Millions, $ in Millions, $ in Millions | 1 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Mar. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Jul. 31, 2018 USD ($) | Jun. 30, 2018 USD ($) t | Dec. 31, 2020 USD ($) numberOfMine | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) $ / shares | Dec. 31, 2018 AUD ($) | Dec. 03, 2018 USD ($) | Feb. 06, 2018
Other Commercial Events [Line Items] |  |  |  |  |  |  |  |  |  |
Number of mines idled during period | numberOfMine |  |  |  |  | 9 |  |  |  |  |
Interest in unincorporated joint venture project |  |  |  |  | 50.00% |  |  |  |  |
Contribution to construction and development of joint venture |  |  |  |  | $ 72.0 |  |  |  |  |
Gain on formation of United Wambo Joint Venture |  |  |  |  | 0.0 | $ (48.1) | $ 0.0 |  |  |
Revenues |  |  |  |  | 2,881.1 | 4,623.4 | 5,581.8 |  |  |
Provision for equipment loss |  |  |  |  | 0.0 | 83.2 | 66.4 |  |  |
Insurance recovery |  |  |  |  | 0.0 | 125.0 | 0.0 |  |  |
Proceeds from disposal of assets, net of receivables |  |  |  |  | 27.1 | 30.0 | 76.4 |  |  |
Gain on disposition of assets |  |  |  |  | 15.2 | 2.1 | 48.2 |  |  |
DTA and PBGC |  |  |  |  |  |  |  |  |  |
Other Commercial Events [Line Items] |  |  |  |  |  |  |  |  |  |
Ownership percentage of equity method investment |  |  |  |  |  |  |  |  |  | 50.00%
Red Mountain Joint Venture |  |  |  |  |  |  |  |  |  |
Other Commercial Events [Line Items] |  |  |  |  |  |  |  |  |  |
Proceeds from disposal of assets, net of receivables |  |  |  |  |  |  | 20.0 |  |  |
Gain on disposition of assets |  |  |  |  |  |  | 7.1 |  |  |
Queensland’s Bowen Basin |  |  |  |  |  |  |  |  |  |
Other Commercial Events [Line Items] |  |  |  |  |  |  |  |  |  |
Proceeds from disposal of assets, net of receivables |  |  |  |  |  |  |  | $ 37 |  |
Gain on disposition of assets |  |  |  |  |  |  | 20.6 |  |  |
Shoal Creek |  |  |  |  |  |  |  |  |  |
Other Commercial Events [Line Items] |  |  |  |  |  |  |  |  |  |
Customary purchase price adjustments |  |  |  |  |  |  |  |  | $ 389.8 |
Purchase price allocation, property, plant, equipment and mine development |  |  |  |  |  | 365.3 |  |  |  |
Purchase price allocation, inventories |  |  |  |  |  | 39.9 |  |  |  |
Purchase price allocation, asset retirement obligations |  |  |  |  |  | 11.3 |  |  |  |
Purchase price allocation, current liabilities |  |  |  |  |  | 4.1 |  |  |  |
Revenues |  | $ 12.8 |  |  |  |  | 6,008.4 |  |  |
Net income (loss) attributable to common stockholders |  | $ 0.1 |  |  |  |  |  |  |  |
Excluded acquisition costs |  |  |  |  |  |  | 7.4 |  |  |
Business acquisition, pro forma, income from continuing operations, net of income taxes |  |  |  |  |  |  | $ 826.6 |  |  |
Basic earnings per share from continuing operations (dollars per share) | $ / shares |  |  |  |  |  |  | $ 5.84 |  |  |
Diluted earnings per share from continuing operations (dollars per share) | $ / shares |  |  |  |  |  |  | $ 5.75 |  |  |
Stanmore Coal Limited |  |  |  |  |  |  |  |  |  |
Other Commercial Events [Line Items] |  |  |  |  |  |  |  |  |  |
Coal reserves (in tonnes) | t |  |  |  | 23 |  |  |  |  |  |
Proceeds from disposal of assets, net of receivables |  |  |  | $ 22.0 |  |  |  |  |  |
Gain on disposition of assets |  |  | $ 20.5 |  |  |  |  |  |  |
Wambo Mine |  |  |  |  |  |  |  |  |  |
Other Commercial Events [Line Items] |  |  |  |  |  |  |  |  |  |
Fair value of interest in joint venture |  |  |  |  | 63.7 |  |  |  |  |
Carrying value of net assets |  |  |  |  | 15.6 |  |  |  |  |
North Goonyella Mine |  |  |  |  |  |  |  |  |  |
Other Commercial Events [Line Items] |  |  |  |  |  |  |  |  |  |
Costs related to north goonyella events |  |  |  |  |  |  | $ 58.0 |  |  |
Containment and idling costs |  |  |  |  | $ 32.3 | 111.5 |  |  |  |
Insurance recovery | $ 125.0 |  |  |  |  | 125.0 |  |  |  |
Deductible amount | $ 50.0 |  |  |  |  |  |  |  |  |
North Goonyella Mine | Mine Carrying Value |  |  |  |  |  |  |  |  |  |
Other Commercial Events [Line Items] |  |  |  |  |  |  |  |  |  |
Costs related to north goonyella events |  |  |  |  |  | 300.0 |  |  |  |
Kayenta Mine |  |  |  |  |  |  |  |  |  |
Other Commercial Events [Line Items] |  |  |  |  |  |  |  |  |  |
Consideration held in trust upon termination of coal supply agreement |  |  |  |  |  | 53.5 |  |  |  |
Receivable for additional consideration on settlement, total |  |  |  |  |  | 78.5 |  |  |  |
Receivable for additional consideration on settlement |  |  |  |  |  | $ 35.4 |  |  |  |

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