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Long-term Debt - Textual (Details) - USD ($) |  | 1 Months Ended | 12 Months Ended | 54 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Jan. 29, 2021 | Apr. 30, 2018 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Sep. 30, 2021 | Jan. 14, 2022 | Jun. 04, 2021 | Apr. 03, 2017 | Feb. 15, 2017
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Debt issuance cost |  |  | $ 34,800,000 | $ 42,700,000 |  |  |  |  |  |
Interest expense |  |  | 183,400,000 | 139,800,000 | $ 144,000,000.0 |  |  |  |  |
Net (gain) loss on early debt extinguishment |  |  | 33,200,000 | $ 0 | (200,000) |  |  |  |  |
Professional Fees |  |  | $ 10,600,000 |  |  |  |  |  |  |
Common Stock, shares authorized (in shares) |  |  | 450,000,000.0 | 450,000,000.0 |  |  |  |  |  |
Common Stock, shares issued (in shares) |  |  | 176,300,000 | 140,500,000 |  |  |  |  |  |
Payment for debt exchange | $ 9,400,000 |  |  |  |  |  |  |  |  |
Payment for debt exchange early tender premiums | 4,000,000 |  |  |  |  |  |  |  |  |
Proceeds from common stock issuances, net of costs |  |  | $ 269,800,000 | $ 0 | $ 0 |  |  |  |  |
At Market Issuance |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Common Stock, shares authorized (in shares) |  |  | 32,500,000 |  |  |  |  | 12,500,000 |  |
Sale of Stock, Number of Shares Issued in Transaction |  |  | 24,800,000 |  |  |  |  |  |  |
Common Stock, shares issued (in shares) |  |  | 24,800,000 | 0 | 0 |  |  |  |  |
At Market Issuance | Common Stock |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Proceeds from common stock issuances, net of costs |  |  | $ 269,800,000 |  |  |  |  |  |  |
Open Market Purchase |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Payment for debt extinguishment or debt prepayment cost |  |  | 232,400,000 |  |  |  |  |  |  |
Net (gain) loss on early debt extinguishment |  |  | (28,800,000) |  |  |  |  |  |  |
Write off of deferred debt issuance cost |  |  | 9,700,000 |  |  |  |  |  |  |
Debt for Equity Exchange |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Net (gain) loss on early debt extinguishment |  |  | $ 900,000 |  |  |  |  |  |  |
Common Stock, shares issued (in shares) |  |  | 10,000,000 | 0 | 0 |  |  |  |  |
Accounts Receivable Securitization Program, April 3, 2020 |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Line of credit facility, remaining borrowing capacity |  |  | $ 26,300,000 |  |  |  |  |  |  |
Exit facility, maximum borrowing capacity |  |  |  |  |  |  |  |  | $ 250,000,000 |
Senior Notes | 6.000% Senior Secured Notes due March 2022 (2022 Notes) |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  | $ 23,100,000 | $ 459,000,000.0 |  |  |  |  |  |
Stated interest rate |  |  | 6.00% |  |  |  |  |  |  |
Aggregate principal amount of debt exchanged | 398,700,000 |  |  |  |  |  |  |  |  |
Senior Notes | 6.000% Senior Secured Notes due March 2022 (2022 Notes) | Debt for Equity Exchange |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Proceeds from common stock issuances, net of costs |  |  | $ 37,300,000 |  |  |  |  |  |  |
Senior Notes | 6.375% Senior Secured Notes due March 2025 (2025 Notes) |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  | $ 334,900,000 | 500,000,000.0 |  |  |  |  |  |
Stated interest rate |  |  | 6.375% |  |  |  |  |  |  |
Interest expense |  |  | $ 35,700,000 | 36,700,000 | $ 36,300,000 |  |  |  |  |
Debt Issuance Costs, Gross |  |  |  |  |  |  |  |  |  | $ 25,100,000
Senior Notes | 6.375% Senior Secured Notes due March 2025 (2025 Notes) | Open Market Purchase |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Retirement of Debt |  |  | 117,800,000 |  |  |  |  |  |  |
Senior Notes | 6.375% Senior Secured Notes due March 2025 (2025 Notes) | Debt for Equity Exchange |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Proceeds from common stock issuances, net of costs |  |  | $ 47,200,000 |  |  |  |  |  |  |
Senior Notes | 6.375% Senior Secured Notes due March 2025 (2025 Notes) | Geographic Distribution, Domestic |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Collateral, Capital Stock, Percent |  |  | 100.00% |  |  |  |  |  |  |
Senior Notes | 6.375% Senior Secured Notes due March 2025 (2025 Notes) | Geographic Distribution, Foreign |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Collateral, Nonvoting Capital Stock, Percent |  |  | 100.00% |  |  |  |  |  |  |
Senior Notes | 6.375% Senior Secured Notes due March 2025 (2025 Notes) | Effect of Plan |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Debt principal amount |  |  |  |  |  |  |  |  |  | $ 500,000,000
Senior Notes | 10.00% Senior Secured Notes Due 2024 (New Co-Issuer Notes) |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Debt principal amount | 193,900,000 |  |  |  |  |  |  |  |  |
Stated interest rate |  |  | 10.00% |  |  |  |  |  |  |
Long-term debt |  |  | $ 193,900,000 | 0 |  |  |  |  |  |
Debt covenant, liquidity attributable to co-issuers limit (minimum) | $ 60,000,000 |  |  |  |  |  |  |  |  |
Debt secured liens term, percentage of capital stock | 100.00% |  |  |  |  |  |  |  |  |
Interest and Debt Expense |  |  | $ 19,600,000 |  |  |  |  |  |  |
Debt Issuance Costs, Gross | $ 5,600,000 |  |  |  |  |  |  |  |  |
Senior Notes | 8.500% Senior Secured Notes due 2024 (New Peabody Notes) |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Debt principal amount | 195,100,000 |  |  |  |  |  |  |  |  |
Stated interest rate |  |  | 8.50% |  |  |  |  |  |  |
Long-term debt |  |  | $ 62,600,000 | 0 |  |  |  |  |  |
Interest rate per annum paid-in-kind |  |  | 2.50% |  |  |  |  |  |  |
Net (gain) loss on early debt extinguishment |  |  | $ (3,500,000) |  |  |  |  |  |  |
Interest and Debt Expense |  |  | 12,900,000 |  |  |  |  |  |  |
Debt Issuance Costs, Gross | 5,700,000 |  |  |  |  |  |  |  |  |
Paid-in-Kind Interest |  |  | 2,900,000 |  |  |  |  |  |  |
Debt exchange offer, required purchase amount (up to) |  |  | $ 22,400,000 |  |  |  |  |  |  |
Debt exchange offer, required purchase, percentage of accreted value |  |  | 80.00% |  |  |  |  |  |  |
Senior Notes | 8.500% Senior Secured Notes due 2024 (New Peabody Notes) | Open Market Purchase |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Retirement of Debt |  |  | $ 91,400,000 |  |  |  |  |  |  |
Senior Notes | 8.500% Senior Secured Notes due 2024 (New Peabody Notes) | Debt for Equity Exchange |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Proceeds from common stock issuances, net of costs |  |  | 21,600,000 |  |  |  |  |  |  |
Senior Notes | 8.500% Senior Secured Notes due 2024 (New Peabody Notes) | Subsequent Event |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Debt exchange offer, required purchase amount (up to) |  |  |  |  |  |  | $ 38,600,000 |  |  |
Debt exchange offer, required purchase, percentage of accreted value |  |  |  |  |  |  | 94.94% |  |  |
Term Loan | Successor Credit Agreement |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Interest expense |  |  | 12,800,000 | 15,600,000 | 22,200,000 |  |  |  |  |
Original issue discount and deferred finance costs |  |  |  | 10,400,000 |  |  |  |  | 37,300,000 |
Debt instrument, periodic payment |  |  | 1,000,000 |  |  |  |  |  |  |
Repayments of debt |  |  |  |  |  | $ 500,000,000 |  |  |  |
Payment for debt extinguishment or debt prepayment cost |  | $ 46,000,000 |  |  |  |  |  |  |  |
Term Loan | Successor Credit Agreement | Effect of Plan |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Debt principal amount |  |  |  |  |  |  |  |  | $ 950,000,000 |
Term Loan | Senior Secured Term Loan Due 2024 |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Debt amount incurred | 206,000,000 |  |  |  |  |  |  |  |  |
Long-term debt |  |  | 206,000,000.0 | 0 |  |  |  |  |  |
Interest and Debt Expense |  |  | 20,500,000 |  |  |  |  |  |  |
Debt Issuance Costs, Gross | 7,100,000 |  |  |  |  |  |  |  |  |
Term Loan | Senior Secured Term Loan Due 2025 |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  | 322,800,000 |  |  |  |  |  |  |
Term Loan | Senior Secured Term Loan Due 2025 | Open Market Purchase |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Retirement of Debt |  |  | 61,700,000 |  |  |  |  |  |  |
Revolving Credit Facility |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Long-term debt |  |  | 0 | 216,000,000.0 |  |  |  |  |  |
Revolving Credit Facility | 2017 Revolver |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Interest expense |  |  | 1,400,000 | $ 15,900,000 | $ 6,200,000 |  |  |  |  |
2019 Revolver commitments, matures 2020 | 0 |  |  |  |  |  |  |  |  |
6.000% Senior Secured Notes due March 2022 (2022 Notes) |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Net (gain) loss on early debt extinguishment |  |  | $ 0 |  |  |  |  |  |  |
London Interbank Offered Rate (LIBOR) | Term Loan | Successor Credit Agreement |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Basis spread on variable rate |  |  | 2.75% |  |  |  |  |  |  |
Revolving Credit Facility | Line of Credit |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Repayments of lines of credit | 10,000,000 |  |  |  |  |  |  |  |  |
Letter of Credit | Line of Credit |  |  |  |  |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |  |  |  |  |
Debt amount incurred | 324,000,000 |  |  |  |  |  |  |  |  |
Revolving credit facility, fee on unused borrowings |  |  | 6.00% |  |  |  |  |  |  |
Debt covenant, unrestricted subsidiaries' liquidity | 200,000,000 |  |  |  |  |  |  |  |  |
Refinancing transactions, principal repurchase basis | 4 |  |  |  |  |  |  |  |  |
Refinancing transactions, principal amount basis for purchase | $ 1 |  |  |  |  |  |  |  |  |
Refinancing transactions, debt repurchases period | 30 days |  |  |  |  |  |  |  |  |
Interest and Debt Expense |  |  | $ 21,900,000 |  |  |  |  |  |  |
Debt Issuance Costs, Gross | $ 4,100,000 |  |  |  |  |  |  |  |  |
Commitment fee percentage |  |  | 0.50% |  |  |  |  |  |  |
Debt covenant, aggregate liquidity at the end of each quarter | $ 125,000,000 |  |  |  |  |  |  |  |  |

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