Document and Entity Information - shares shares in Millions	3 Months Ended
	Mar. 31, 2018	May 04, 2018
Entity Information [Line Items]
Entity Registrant Name	PEABODY ENERGY CORP
Entity Central Index Key	0001064728
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		125.5