Consolidated Statements of Common Stockholders' Equity (FirstEnergy Corp.) - USD ($) $ in Millions	Total	Common Stock	Other Paid-In Capital	Accumulated Other Comprehensive Income	Retained Earnings
Beginning Balance, Shares at Dec. 31, 2012		418,216,437
Beginning Balance at Dec. 31, 2012		$ 42	$ 9,769	$ 385	$ 2,888
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 392				392
Amortized 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, Shares at Dec. 31, 2013		418,628,559
Ending Balance at Dec. 31, 2013		$ 42	9,776	284	2,590
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 299				299
Amortized 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, Shares at Dec. 31, 2014	421,102,570	421,102,570
Ending Balance at Dec. 31, 2014	$ 12,420	$ 42	9,847	246	2,285
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	$ 578				578
Amortized loss on derivative hedges, net of income taxes				4
Change in unrealized gain on investments, net of income taxes				(7)
Pensions and OPEB, net of income taxes				(72)
Stock-based compensation			45
Cash dividends declared on common stock					(607)
Stock issuance - employee benefits, Shares		2,457,827
Stock issuance - employee benefits			60
Ending Balance, Shares at Dec. 31, 2015	423,560,397	423,560,397
Ending Balance at Dec. 31, 2015	$ 12,421	$ 42	$ 9,952	$ 171	$ 2,256