Emergence from the Chapter 11 Cases and Fresh Start Reporting - Treatment of Classified Claims and Interest (Details) - Effect of Plan	Apr. 01, 2017 USD ($) $ / shares
Second Lien Notes Claims (Classes 2A - 2D)
Fresh-Start Adjustment [Line Items]
Cash claims, amount to be recovered	$ 450,000,000
Common stock, par value per share (in dollars per share) | $ / shares	$ 0.01
United Mine Workers of America 1974 Pension Plan Claim (Classes 7A - 7E)
Fresh-Start Adjustment [Line Items]
Cash claims, amount to be recovered	$ 75
Cash claims, payment period	5 years
Unsecured Subordinated Debentures Claims (Class 8A)
Fresh-Start Adjustment [Line Items]
Fees and expenses of trustee	$ 350,000
Ceiling of penny warrants exercisable, as percent of common stock	1.00%
Peabody Energy | General Unsecured Claims
Fresh-Start Adjustment [Line Items]
Cash amount from which claimants receive pro rata share	$ 5,000,000
Cash claims, maximum additional amount to be recovered by claimants under plan	$ 2,000,000
Peabody Energy | Convenience Claims, Class 6A
Fresh-Start Adjustment [Line Items]
Cash claims, threshold percent	72.50%
Encumbered Guarantor Debtors | General Unsecured Claims
Fresh-Start Adjustment [Line Items]
Cash claims, amount to be recovered	$ 75,000,000
Encumbered Guarantor Debtors | Convenience Claims, Class 6B
Fresh-Start Adjustment [Line Items]
Cash claims, threshold percent	72.50%
Maximum | Peabody Energy | Convenience Claims, Class 6A
Fresh-Start Adjustment [Line Items]
Cash claims, amount to be recovered	$ 2,000,000
Maximum | Encumbered Guarantor Debtors | Convenience Claims, Class 6B
Fresh-Start Adjustment [Line Items]
Cash claims, amount to be recovered	$ 0