Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2020	Jan. 29, 2021	Jun. 30, 2020
Document Information [Line Items]
Entity Central Index Key	0001710366
Entity Registrant Name	CONSOL Energy Inc
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2020
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Document Transition Report	false
Entity File Number	001-38147
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	82-1954058
Entity Address, Address Line One	1000 CONSOL Energy Drive, Suite 100
Entity Address, City or Town	Canonsburg
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	15317-6506
City Area Code	724
Local Phone Number	416-8300
Title of 12(b) Security	Common Stock ($0.01 par value)
Trading Symbol	CEIX
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 133,696,610
Entity Common Stock, Shares Outstanding		34,031,374