Document and Entity Information	3 Months Ended
	Mar. 31, 2019 shares
Document and Entity Information [Abstract]
Entity Registrant Name	FIRSTENERGY CORP
Entity Central Index Key	0001031296
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Amendment Flag	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock Shares Outstanding	531,442,309