Accumulated Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	$ 284	$ 385	$ 426
Other comprehensive income before reclassifications (1)	105	52	120
Amounts reclassified from AOCI	(143)	(153)	(161)
Other comprehensive loss, net of tax	(38)	(101)	(41)
AOCI Ending Balance	246	284	385
Tax on unrealized gains	10	(4)	(2)
FES
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	54	72	76
Other comprehensive income before reclassifications (1)	58	29	54
Amounts reclassified from AOCI	(55)	(47)	(58)
Other comprehensive loss, net of tax	3	(18)	(4)
AOCI Ending Balance	57	54	72
Tax on unrealized gains	8	(3)	(2)
Gains & Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	(36)	(38)	(39)
Other comprehensive income before reclassifications (1)	0	0	0
Amounts reclassified from AOCI	(1)	2	1
Other comprehensive loss, net of tax	(1)	2	1
AOCI Ending Balance	(37)	(36)	(38)
Gains & Losses on Cash Flow Hedges | FES
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	(1)	3	8
Other comprehensive income before reclassifications (1)	0	0	0
Amounts reclassified from AOCI	(6)	(4)	(5)
Other comprehensive loss, net of tax	(6)	(4)	(5)
AOCI Ending Balance	(7)	(1)	3
Tax on unrealized gains			1
Unrealized Gains on AFS Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	9	15	19
Other comprehensive income before reclassifications (1)	55	29	41
Amounts reclassified from AOCI	(39)	(35)	(45)
Other comprehensive loss, net of tax	16	(6)	(4)
AOCI Ending Balance	25	9	15
Tax on unrealized gains	39	17	25
Unrealized Gains on AFS Securities | FES
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	8	13	16
Other comprehensive income before reclassifications (1)	50	26	38
Amounts reclassified from AOCI	(37)	(31)	(41)
Other comprehensive loss, net of tax	13	(5)	(3)
AOCI Ending Balance	21	8	13
Tax on unrealized gains	30	15	22
Defined Benefit Pension & OPEB Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	311	408	446
Other comprehensive income before reclassifications (1)	50	23	79
Amounts reclassified from AOCI	(103)	(120)	(117)
Other comprehensive loss, net of tax	(53)	(97)	(38)
AOCI Ending Balance	258	311	408
Tax on unrealized gains	34	12	(3)
Defined Benefit Pension & OPEB Plans | FES
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	47	56	52
Other comprehensive income before reclassifications (1)	8	3	16
Amounts reclassified from AOCI	(12)	(12)	(12)
Other comprehensive loss, net of tax	(4)	(9)	4
AOCI Ending Balance	43	47	56
Tax on unrealized gains	$ 5	$ 2	$ 9