Supplemental Guarantor Information (Details 2) - USD ($) $ in Millions			1 Months Ended	12 Months Ended
	Dec. 13, 2016	Feb. 12, 2014	Dec. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Consolidated Statements of Cash Flows [Abstract]
NET CASH PROVIDED FROM (USED FOR) OPERATING ACTIVITIES				$ 3,371	$ 3,447	$ 2,713
New Financing-
Long-term debt				1,976	1,311	4,528
Short-term borrowings, net				975	0	0
Equity contribution from parent	$ 500		$ 500
Redemptions and Repayments-
Long-term debt				(2,331)	(879)	(1,759)
Short-term borrowings, net				0	(91)	(1,605)
Common stock dividend payments				(611)	(607)	(604)
Other				(31)	(13)	(47)
Net cash (used for) provided from financing activities				(22)	(279)	513
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions				(2,835)	(2,704)	(3,312)
Nuclear fuel				(232)	(190)	(233)
Proceeds from asset sales		$ 394		15	20	394
Sales of investment securities held in trusts				1,678	1,534	2,133
Purchases of investment securities held in trusts				(1,789)	(1,648)	(2,236)
Other				27	8	48
Net cash used for investing activities				(3,281)	(3,122)	(3,359)
Net change in cash and cash equivalents				68	46	(133)
Cash and cash equivalents at beginning of period				131	85	218
Cash and cash equivalents at end of period			199	199	131	85
Eliminations
Consolidated Statements of Cash Flows [Abstract]
NET CASH PROVIDED FROM (USED FOR) OPERATING ACTIVITIES				(25)	(24)	(22)
New Financing-
Long-term debt				0	0	0
Short-term borrowings, net				(941)	(863)	(361)
Equity contribution from parent						0
Redemptions and Repayments-
Long-term debt				25	24	22
Short-term borrowings, net					(98)	(178)
Common stock dividend payments					0
Other					0	0
Net cash (used for) provided from financing activities				(916)	(937)	(517)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions				0	0	0
Nuclear fuel				0	0	0
Proceeds from asset sales				0	0	0
Sales of investment securities held in trusts				0	0	0
Purchases of investment securities held in trusts				0	0	0
Cash investments				0	0
Loans to affiliated companies, net				941	961	539
Other				0	0	0
Net cash used for investing activities				941	961	539
Net change in cash and cash equivalents				0	0	0
Cash and cash equivalents at beginning of period				0	0	0
Cash and cash equivalents at end of period			0	0	0	0
FES
Consolidated Statements of Cash Flows [Abstract]
NET CASH PROVIDED FROM (USED FOR) OPERATING ACTIVITIES				(842)	(637)	(600)
New Financing-
Long-term debt				0	0	0
Short-term borrowings, net				948	796	247
Equity contribution from parent						500
Redemptions and Repayments-
Long-term debt				0	(17)	(1)
Short-term borrowings, net					0	0
Common stock dividend payments					(70)
Other					0	(1)
Net cash (used for) provided from financing activities				948	709	745
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions				(30)	(5)	(8)
Nuclear fuel				0	0	0
Proceeds from asset sales				9	10	0
Sales of investment securities held in trusts				0	0	0
Purchases of investment securities held in trusts				0	0	0
Cash investments				10	(10)
Loans to affiliated companies, net				(95)	(67)	(136)
Other				0	0	(1)
Net cash used for investing activities				(106)	(72)	(145)
Net change in cash and cash equivalents				0	0	0
Cash and cash equivalents at beginning of period				0	0	0
Cash and cash equivalents at end of period			0	0	0	0
FG
Consolidated Statements of Cash Flows [Abstract]
NET CASH PROVIDED FROM (USED FOR) OPERATING ACTIVITIES				549	551	408
New Financing-
Long-term debt				186	45	431
Short-term borrowings, net				94	67	114
Equity contribution from parent						0
Redemptions and Repayments-
Long-term debt				(224)	(70)	(269)
Short-term borrowings, net					0	0
Common stock dividend payments					0
Other				(6)	(5)	(12)
Net cash (used for) provided from financing activities				50	37	264
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions				(224)	(223)	(169)
Nuclear fuel				0	0	0
Proceeds from asset sales				0	3	307
Sales of investment securities held in trusts				0	0	0
Purchases of investment securities held in trusts				0	0	0
Cash investments				0	0
Loans to affiliated companies, net				(376)	(372)	(815)
Other				1	4	5
Net cash used for investing activities				(599)	(588)	(672)
Net change in cash and cash equivalents				0	0	0
Cash and cash equivalents at beginning of period				2	2	2
Cash and cash equivalents at end of period			2	2	2	2
NG
Consolidated Statements of Cash Flows [Abstract]
NET CASH PROVIDED FROM (USED FOR) OPERATING ACTIVITIES				1,103	1,261	785
New Financing-
Long-term debt				285	296	447
Short-term borrowings, net				0	0	0
Equity contribution from parent						0
Redemptions and Repayments-
Long-term debt				(308)	(348)	(568)
Short-term borrowings, net					(28)	(123)
Common stock dividend payments					0
Other				(2)	(1)	(2)
Net cash (used for) provided from financing activities				(25)	(81)	(246)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions				(292)	(399)	(662)
Nuclear fuel				(232)	(190)	(233)
Proceeds from asset sales				0	0	0
Sales of investment securities held in trusts				717	733	1,163
Purchases of investment securities held in trusts				(783)	(791)	(1,219)
Cash investments				0	0
Loans to affiliated companies, net				(488)	(533)	412
Other				0	0	0
Net cash used for investing activities				(1,078)	(1,180)	(539)
Net change in cash and cash equivalents				0	0	0
Cash and cash equivalents at beginning of period				0	0	0
Cash and cash equivalents at end of period			0	0	0	0
FES
Consolidated Statements of Cash Flows [Abstract]
NET CASH PROVIDED FROM (USED FOR) OPERATING ACTIVITIES				785	1,151	571
New Financing-
Long-term debt				471	341	878
Short-term borrowings, net				101	0	0
Equity contribution from parent				0		500
Redemptions and Repayments-
Long-term debt				(507)	(411)	(816)
Short-term borrowings, net				0	(126)	(301)
Common stock dividend payments				0	(70)	0
Other				(8)	(6)	(15)
Net cash (used for) provided from financing activities				57	(272)	246
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions				(546)	(627)	(839)
Nuclear fuel				(232)	(190)	(233)
Proceeds from asset sales		$ 307		9	13	307
Sales of investment securities held in trusts				717	733	1,163
Purchases of investment securities held in trusts				(783)	(791)	(1,219)
Cash investments				10	(10)	0
Loans to affiliated companies, net				(18)	(11)	0
Other				1	4	4
Net cash used for investing activities				(842)	(879)	(817)
Net change in cash and cash equivalents				0	0	0
Cash and cash equivalents at beginning of period				2	2	2
Cash and cash equivalents at end of period			$ 2	$ 2	$ 2	$ 2