XML 12 R1.htm IDEA: XBRL DOCUMENT v3.8.0.1
Document and Entity Information
 9 Months Ended
Sep. 30, 2017
shares
Entity Information [Line Items]  
Entity Registrant Name FIRSTENERGY CORP
Entity Central Index Key 0001031296
Document Type 10-Q
Document Period End Date Sep. 30, 2017
Amendment Flag false
Document Fiscal Year Focus 2017
Document Fiscal Period Focus Q3
Current Fiscal Year End Date --12-31
Entity Filer Category Large Accelerated Filer
Entity Common Stock Shares Outstanding 444,858,003
FES  
Entity Information [Line Items]  
Entity Registrant Name FirstEnergy Solutions Corp.
Entity Central Index Key 0001407703
Document Type 10-Q
Document Period End Date Sep. 30, 2017
Amendment Flag false
Document Fiscal Year Focus 2017
Document Fiscal Period Focus Q3
Current Fiscal Year End Date --12-31
Entity Filer Category Non-accelerated Filer
Entity Common Stock Shares Outstanding 7