Cover Page - shares shares in Millions	6 Months Ended
	Jun. 30, 2021	Aug. 02, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2021
Document Transition Report	false
Entity File Number	1-16463
Entity Registrant Name	PEABODY ENERGY CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	13-4004153
Entity Address, Address Line One	701 Market Street,
Entity Address, City or Town	St. Louis,
Entity Address, State or Province	MO
Entity Address, Postal Zip Code	63101-1826
City Area Code	314
Local Phone Number	342-3400
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	BTU
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Bankruptcy Proceedings, Reporting Current	true
Entity Common Stock, Shares Outstanding		114.3
Entity Central Index Key	0001064728
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Amendment Flag	false