Long-term Debt - Schedule of Debt (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2022 USD ($) buyer $ / shares shares	Dec. 31, 2022 USD ($) buyer $ / shares shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares	Mar. 01, 2025 USD ($)	Mar. 31, 2022 USD ($)	Mar. 07, 2022 USD ($)	Mar. 01, 2022 USD ($)	Feb. 24, 2022 $ / shares	Mar. 31, 2021	Jan. 29, 2021 USD ($)
Debt Instrument [Line Items]
Finance Lease, Liability	$ 23,600,000	$ 23,600,000	$ 29,300,000
Less: Debt issuance costs	(9,800,000)	(9,800,000)	(34,800,000)
Long-term Debt and Lease Obligation, Including Current Maturities	333,800,000	333,800,000	1,137,800,000
Less: Current portion of long-term debt	13,200,000	13,200,000	59,600,000
Long-term debt	$ 320,600,000	320,600,000	1,078,200,000
Interest expense		140,300,000	183,400,000	$ 139,800,000
Financial Assurance Instruments		53,300,000	51,100,000	35,400,000
Interest Paid, Capitalized, Investing Activities		118,500,000	174,900,000	126,900,000
Noncash interest expense, net		$ 17,700,000	$ 21,300,000	16,200,000
Common Stock, shares authorized (in shares) | shares	450,000,000.0	450,000,000.0	450,000,000.0
Proceeds from common stock issuances, net of costs		$ 222,000,000.0	$ 269,800,000	0
Common Stock, shares issued (in shares) | shares	187,100,000	187,100,000	176,300,000
Net loss (gain) on early debt extinguishment		$ (57,900,000)	$ 33,200,000	$ 0
Letter of Credit
Debt Instrument [Line Items]
Stated interest rate	0.75%	0.75%
Exit facility, maximum borrowing capacity	$ 250,000,000	$ 250,000,000
Convertible Debt
Debt Instrument [Line Items]
Shares Issued, Price Per Share | $ / shares									$ 14.98
Common Stock
Debt Instrument [Line Items]
Common Stock, shares authorized (in shares) | shares	450,000,000	450,000,000
At Market Issuance
Debt Instrument [Line Items]
Common Stock, shares authorized (in shares) | shares			32,500,000
Sale of Stock, Number of Shares Issued in Transaction | shares			24,800,000
Common Stock, shares issued (in shares) | shares	10,100,000	10,100,000	24,800,000	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
Debt for Equity Exchange
Debt Instrument [Line Items]
Common Stock, shares issued (in shares) | shares	0	0	10,000,000	0
3.250% Convertible Senior Notes due March 2028
Debt Instrument [Line Items]
Debt Instrument, Convertible, Threshold Trading Days | buyer	20
Debt Instrument, Convertible, Threshold Consecutive Trading Days | buyer	30
Indebtedness
Debt Instrument [Line Items]
Interest expense		$ 87,000,000.0	$ 132,300,000	$ 104,400,000
10.000% Senior Secured Notes due December 2024 and Senior Secured Term Loan due 2024
Debt Instrument [Line Items]
Payment for debt extinguishment or debt prepayment cost		18,500,000
Debt covenant, liquidity attributable to co-issuers limit (minimum)	$ 60,000,000	60,000,000
8.500% Senior Secured Notes due December 2024 and 6.375% Senior Secured Notes due March 2025 [Domain]
Debt Instrument [Line Items]
Net loss (gain) on early debt extinguishment		23,000,000
10.00% Revolving Credit Facility maturing 2025
Debt Instrument [Line Items]
Exit facility, maximum borrowing capacity						$ 225,000,000
Proceeds from Issuance or Sale of Equity		$ 222,000,000
10.00% Revolving Credit Facility maturing 2025 | At Market Issuance | Common Stock
Debt Instrument [Line Items]
Sale of Stock, Number of Shares Issued in Transaction | shares		10,100,000
Senior Notes | 6.000% Senior Secured Notes due March 2022 (2022 Notes)
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 0	23,100,000
Stated interest rate	6.00%	6.00%
Debt repurchase, amount		$ 23,100,000
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	$ 0	$ 0	334,900,000
Stated interest rate	6.375%	6.375%
Payment for debt extinguishment or debt prepayment cost		$ 66,100,000
Debt repurchase, amount		$ 257,400,000
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 | 8.500% Senior Secured Notes due 2024 (New Peabody Notes)
Debt Instrument [Line Items]
Stated interest rate	8.50%	8.50%
Long-term debt	$ 0	$ 0	62,600,000
Debt exchange offer, required purchase, percentage of accreted value						25.00%				80.00%
Debt repurchase, amount		$ 62,500,000
Debt principal amount											$ 195,100,000
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 | 10.00% Senior Secured Notes Due 2024 (New Co-Issuer Notes)
Debt Instrument [Line Items]
Stated interest rate	10.00%	10.00%
Long-term debt	$ 0	$ 0	193,900,000
Debt principal amount											193,900,000
Senior Notes | 3.250% Convertible Senior Notes due March 2028
Debt Instrument [Line Items]
Stated interest rate	3.25%	3.25%
Long-term debt	$ 320,000,000.0	$ 320,000,000.0	0
Debt principal amount						$ 320,000,000		$ 320,000,000
Debt Issuance Costs, Gross	$ 11,200,000	$ 11,200,000
Common Stock, Excess of the Conversion Price, Percentage	130.00%	130.00%
Debt Instrument, Convertible, Threshold Consecutive Trading Days | buyer		30
Debt Instrument, Principle Amount	$ 1,000	$ 1,000
Principle Amount, Percentage	98.00%	98.00%
Debt Instrument, Convertible, Conversion Ratio | shares	50.3816	50.3816
Debt Instrument, Convertible, Conversion Price | $ / shares	$ 19.85	$ 19.85
Conversion Price Premium, Percent									32.50%
Senior Notes | 3.250% Convertible Senior Notes due March 2028 | Minimum
Debt Instrument [Line Items]
Debt Instrument, Convertible, Threshold Consecutive Trading Days | buyer	20
Senior Notes | 3.250% Convertible Senior Notes due March 2028 | Subsequent Event
Debt Instrument [Line Items]
Principle Amount, Percentage					100.00%
Aggregate Principle Amount, Notes Outstanding					$ 75,000,000
Senior Notes | 10.000% Senior Secured Notes due December 2024 and Senior Secured Term Loan due 2024
Debt Instrument [Line Items]
Payment for debt extinguishment or debt prepayment cost		$ 28,100,000
Senior Notes | 10.00% Revolving Credit Facility maturing 2025
Debt Instrument [Line Items]
Stated interest rate	10.00%	10.00%
Exit facility, maximum borrowing capacity							$ 150,000,000
Term Loan | Senior Secured Term Loan due 2025, net of original issue discount
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 0	322,800,000
Term Loan | Senior Secured Term Loan Due 2024
Debt Instrument [Line Items]
Long-term debt	0	0	206,000,000.0
Payment for debt extinguishment or debt prepayment cost		2,900,000
Term Loan | Senior Secured Term Loan Due 2025
Debt Instrument [Line Items]
Payment for debt extinguishment or debt prepayment cost		276,200,000
Debt repurchase, amount		44,100,000
Term Loan | Senior Secured Term Loan Due 2025 | Open Market Purchase
Debt Instrument [Line Items]
Retirement of Debt			$ 61,700,000
Line of Credit
Debt Instrument [Line Items]
Debt secured liens term, percentage of capital stock			100.00%
Line of Credit | Letter of Credit
Debt Instrument [Line Items]
Debt covenant, aggregate liquidity at the end of each quarter	$ 125,000,000	$ 125,000,000									$ 125,000,000