Consolidated Statements of Common Stockholders' Equity (FirstEnergy Corp.) (USD $) In Millions, except Share data, unless otherwise specified	Total	Common Stock	Other Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings (Accumulated Deficit)
Beginning Balance at Dec. 31, 2011		$ 42	$ 9,765	$ 426	$ 3,047
Beginning Balance, Shares at Dec. 31, 2011		418,216,437
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Earnings available to Parent	770				770
Change in unrealized loss on derivative hedges, net of income taxes				2
Change in unrealized gain on investments, net of income taxes				(4)
Pensions and OPEB, net of income taxes				(39)
Stock-based compensation			4
Cash dividends declared on common stock					(920)
Equity method adjustment (Note 9)	(9)				9
Ending Balance at Dec. 31, 2012		42	9,769	385	2,888
Beginning Balance, Shares at Dec. 31, 2012		418,216,437
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Earnings available to Parent	392				392
Change in unrealized loss on derivative hedges, net of income taxes				2
Change in unrealized gain on investments, net of income taxes				(6)
Pensions and OPEB, net of income taxes				(97)
Stock-based compensation			(4)
Cash dividends declared on common stock					(690)
Stock issuance - employee benefits, Shares		412,122
Stock issuance - employee benefits			11
Ending Balance at Dec. 31, 2013	12,692	42	9,776	284	2,590
Ending Balance, Shares at Dec. 31, 2013	418,628,559	418,628,559
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Earnings available to Parent	299				299
Change in unrealized loss on derivative hedges, net of income taxes				(1)
Change in unrealized gain on investments, net of income taxes				16
Pensions and OPEB, net of income taxes				(53)
Stock-based compensation			20
Cash dividends declared on common stock					(604)
Stock issuance - employee benefits, Shares		2,474,011
Stock issuance - employee benefits			51
Ending Balance at Dec. 31, 2014	$ 12,420	$ 42	$ 9,847	$ 246	$ 2,285
Ending Balance, Shares at Dec. 31, 2014	421,102,570	421,102,570