Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	$ 179	$ 230	$ 171	$ 246
Other comprehensive income before reclassifications	47	(7)	88	7
Amounts reclassified from AOCI	(28)	(38)	(57)	(78)
Other comprehensive income (loss)	19	(45)	31	(71)
Income taxes (benefits) on other comprehensive income (loss)	7	(17)	11	(27)
Other comprehensive income (loss), net of tax	12	(28)	20	(44)
AOCI Ending Balance	191	202	191	202
FES
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	58	56	46	57
Other comprehensive income before reclassifications	44	(7)	80	6
Amounts reclassified from AOCI	(15)	(10)	(32)	(25)
Other comprehensive income (loss)	29	(17)	48	(19)
Income taxes (benefits) on other comprehensive income (loss)	12	(6)	19	(7)
Other comprehensive income (loss), net of tax	17	(11)	29	(12)
AOCI Ending Balance	75	45	75	45
Gains & Losses on Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	(32)	(36)	(33)	(37)
Other comprehensive income before reclassifications	0	0	0	0
Amounts reclassified from AOCI	2	1	4	2
Other comprehensive income (loss)	2	1	4	2
Income taxes (benefits) on other comprehensive income (loss)	1	1	2	1
Other comprehensive income (loss), net of tax	1	0	2	1
AOCI Ending Balance	(31)	(36)	(31)	(36)
Gains & Losses on Cash Flow Hedges | FES
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	(9)	(8)	(9)	(7)
Other comprehensive income before reclassifications	0	0	0	0
Amounts reclassified from AOCI	(1)	(1)	(1)	(2)
Other comprehensive income (loss)	(1)	(1)	(1)	(2)
Income taxes (benefits) on other comprehensive income (loss)	0	0	0	0
Other comprehensive income (loss), net of tax	(1)	(1)	(1)	(2)
AOCI Ending Balance	(10)	(9)	(10)	(9)
Unrealized Gains on AFS Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	36	28	18	25
Other comprehensive income before reclassifications	47	(7)	88	7
Amounts reclassified from AOCI	(12)	(7)	(25)	(17)
Other comprehensive income (loss)	35	(14)	63	(10)
Income taxes (benefits) on other comprehensive income (loss)	13	(5)	23	(4)
Other comprehensive income (loss), net of tax	22	(9)	40	(6)
AOCI Ending Balance	58	19	58	19
Unrealized Gains on AFS Securities | FES
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	30	24	16	21
Other comprehensive income before reclassifications	44	(7)	80	6
Amounts reclassified from AOCI	(11)	(5)	(24)	(15)
Other comprehensive income (loss)	33	(12)	56	(9)
Income taxes (benefits) on other comprehensive income (loss)	13	(4)	22	(4)
Other comprehensive income (loss), net of tax	20	(8)	34	(5)
AOCI Ending Balance	50	16	50	16
Defined Benefit Pension & OPEB Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	175	238	186	258
Other comprehensive income before reclassifications	0	0	0	0
Amounts reclassified from AOCI	(18)	(32)	(36)	(63)
Other comprehensive income (loss)	(18)	(32)	(36)	(63)
Income taxes (benefits) on other comprehensive income (loss)	(7)	(13)	(14)	(24)
Other comprehensive income (loss), net of tax	(11)	(19)	(22)	(39)
AOCI Ending Balance	164	219	164	219
Defined Benefit Pension & OPEB Plans | FES
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
AOCI Beginning Balance	37	40	39	43
Other comprehensive income before reclassifications	0	0	0	0
Amounts reclassified from AOCI	(3)	(4)	(7)	(8)
Other comprehensive income (loss)	(3)	(4)	(7)	(8)
Income taxes (benefits) on other comprehensive income (loss)	(1)	(2)	(3)	(3)
Other comprehensive income (loss), net of tax	(2)	(2)	(4)	(5)
AOCI Ending Balance	$ 35	$ 38	$ 35	$ 38