Consolidated Statements of Comprehensive Income (FirstEnergy Corp.) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
NET INCOME	$ 299us-gaap_ProfitLoss	$ 392us-gaap_ProfitLoss	$ 771us-gaap_ProfitLoss
OTHER COMPREHENSIVE INCOME (LOSS):
Pension and OPEB prior service costs	(76)	(160)	(115)
Amortized gains (losses) on derivative hedges	(2)	3	1
Change in unrealized gain on available-for-sale securities	26	(10)	(6)
Other comprehensive income (loss)	(52)	(167)	(120)
Income tax benefits on other comprehensive loss	(14)us-gaap_OtherComprehensiveIncomeLossTax	(66)us-gaap_OtherComprehensiveIncomeLossTax	(79)us-gaap_OtherComprehensiveIncomeLossTax
Other comprehensive loss, net of tax	(38)	(101)	(41)
COMPREHENSIVE INCOME (LOSS)	261	291	730
Comprehensive income attributable to noncontrolling interest	0	0	1
COMPREHENSIVE INCOME AVAILABLE TO FIRSTENERGY CORP.	$ 261us-gaap_ComprehensiveIncomeNetOfTax	$ 291us-gaap_ComprehensiveIncomeNetOfTax	$ 729us-gaap_ComprehensiveIncomeNetOfTax

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount before tax, after reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount before tax, after reclassification adjustments of other comprehensive income (loss).

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Amount before tax, after reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount of tax expense (benefit) allocated to other comprehensive income (loss).

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