Consolidated Statements of Cash Flows (FirstEnergy Solutions Corp.) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ (1,724)	$ (6,177)	$ 578
Adjustments to reconcile net income (loss) to net cash from operating activities-
Depreciation and amortization, including nuclear fuel, intangible assets and deferred debt-related costs	1,700	1,974	1,826
Investment impairments	13	21	464
Pension and OPEB mark-to-market adjustment	141	147	242
Deferred income taxes and investment tax credits, net	839	(3,063)	284
Deferred costs on sale leaseback transaction, net	49	49	48
Impairment of assets and related charges (Note 2)	2,406	10,665	42
Pension trust contribution	0	(382)	(143)
Gain on investment securities held in trusts	(63)	(50)	(23)
Unrealized (gain) loss on derivative transactions (Note 11)	81	9	(73)
Lease payments on sale and leaseback transaction	(73)	(120)	(131)
Changes in current assets and liabilities-
Receivables	(39)	(11)	184
Materials and supplies	(6)	41	(15)
Prepaid taxes and other	30	27	(10)
Accounts payable	72	(37)	(243)
Accrued taxes	(9)	61	29
Other current liabilities	20	56	69
Cash collateral, net	27	(116)	140
Other	320	142	152
Net cash provided from operating activities	3,808	3,383	3,460
New financing-
Long-term debt	4,675	1,976	1,311
Short-term borrowings, net	0	975	0
Redemptions and Repayments-
Long-term debt	(2,291)	(2,331)	(879)
Short-term borrowings, net	(2,375)	0	(91)
Common stock dividend payments	(639)	(611)	(607)
Other	(72)	(43)	(26)
Net cash used for financing activities	(702)	(34)	(292)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions	(2,587)	(2,835)	(2,704)
Nuclear fuel	(254)	(232)	(190)
Proceeds from asset sales	388	15	20
Sales of investment securities held in trusts	2,170	1,678	1,534
Purchases of investment securities held in trusts	(2,268)	(1,789)	(1,648)
Other	7	27	8
Net cash used for investing activities	(2,716)	(3,281)	(3,122)
Net change in cash and cash equivalents	390	68	46
Cash and cash equivalents at beginning of period	199	131	85
Cash and cash equivalents at end of period	589	199	131
Cash paid (received) during the year -
Interest (net of amounts capitalized)	1,039	1,050	1,028
Income taxes, net of refunds	53	(16)	37
FES
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	(2,391)	(5,455)	82
Adjustments to reconcile net income (loss) to net cash from operating activities-
Depreciation and amortization, including nuclear fuel, intangible assets and deferred debt-related costs	333	633	579
Investment impairments	13	19	90
Pension and OPEB mark-to-market adjustment	24	48	57
Deferred income taxes and investment tax credits, net	455	(2,920)	119
Deferred costs on sale leaseback transaction, net	49	49	48
Impairment of assets and related charges (Note 2)	2,031	8,622	33
Pension trust contribution	0	(138)	0
Gain on investment securities held in trusts	(62)	(48)	(24)
Unrealized (gain) loss on derivative transactions (Note 11)	78	9	(74)
Lease payments on sale and leaseback transaction	(73)	(120)	(131)
Changes in current assets and liabilities-
Receivables	282	89	277
Materials and supplies	(24)	26	(25)
Prepaid taxes and other	43	(8)	14
Accounts payable	(167)	(30)	(76)
Accrued taxes	(71)	76	(26)
Other current liabilities	0	15	43
Cash collateral, net	27	(87)	159
Other	180	6	7
Net cash provided from operating activities	727	786	1,152
New financing-
Long-term debt	0	471	341
Short-term borrowings, net	4	101	0
Redemptions and Repayments-
Long-term debt	(163)	(507)	(411)
Short-term borrowings, net	0	0	(126)
Common stock dividend payments	0	0	(70)
Other	(7)	(9)	(7)
Net cash used for financing activities	(166)	56	(273)
CASH FLOWS FROM INVESTING ACTIVITIES:
Property additions	(275)	(546)	(627)
Nuclear fuel	(254)	(232)	(190)
Proceeds from asset sales	0	9	13
Sales of investment securities held in trusts	940	717	733
Purchases of investment securities held in trusts	(999)	(783)	(791)
Cash investments	(3)	10	(10)
Loans to affiliated companies, net	29	(18)	(11)
Other	0	1	4
Net cash used for investing activities	(562)	(842)	(879)
Net change in cash and cash equivalents	(1)	0	0
Cash and cash equivalents at beginning of period	2	2	2
Cash and cash equivalents at end of period	1	2	2
Cash paid (received) during the year -
Interest (net of amounts capitalized)	128	111	114
Income taxes, net of refunds	(152)	(193)	(5)
Non-cash transaction: Affiliated net asset transfer (Note 14)	$ 73	$ 28	$ 0