Organization and Basis of Presentation - Narrative (Details) customer in Millions	1 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended
	Feb. 12, 2020 USD ($)	Sep. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) mi² agreement entity customer transmission_center company MW	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 16, 2019 USD ($)	Apr. 11, 2019 USD ($)	Jan. 01, 2019 USD ($)	Sep. 26, 2018 USD ($)	Mar. 31, 2018 USD ($)	Aug. 31, 2017 MW	Jun. 30, 2013 USD ($)
Regulatory Assets [Line Items]
Assets				$ 40,063,000,000	$ 42,301,000,000	$ 40,063,000,000	$ 42,257,000,000
Number of regional transmission centers | transmission_center					2
Amount paid to settle claims											$ 225,000,000
Regulatory assets that do not earn a current return				503,000,000	$ 545,000,000	503,000,000
Regulatory assets currently being recovered through deferred returns				290,000,000	228,000,000	$ 290,000,000
Regulatory assets based on prior precedent or anticipated recovery based on rate making premises with specific order					$ 111,000,000
Annual Composite Depreciation Rate					2.70%	2.60%	2.40%
Capitalized financing costs					$ 45,000,000	$ 46,000,000	$ 35,000,000
Interest costs capitalized					26,000,000	19,000,000	17,000,000
Property, plant and equipment				29,911,000,000	31,650,000,000	29,911,000,000
Impairments of long-lived assets					0	0	2,399,000,000
Impact of adopting new accounting pronouncements				35,000,000		35,000,000	(6,000,000)
Net cash used for financing activities					656,000,000	1,394,000,000	(702,000,000)
Purchased power					$ 2,927,000,000	3,109,000,000	2,926,000,000
Number of contracts that may contain variable interest | entity					1
Regulated Distribution
Regulatory Assets [Line Items]
Number of existing utility operating companies | company					10
Number of customers served by utility operating companies | customer					6,000,000
Service Area | mi²					65,000
Plant generation capacity (in MW's) | MW					3,790
Property, plant and equipment, net					$ 2,000,000,000
Property, plant and equipment				20,016,000,000	$ 20,939,000,000	20,016,000,000
Regulated Transmission
Regulatory Assets [Line Items]
Service Area | mi²					24,500
Property, plant and equipment				9,376,000,000	$ 10,166,000,000	9,376,000,000
Bath County, Virginia
Regulatory Assets [Line Items]
Plant generation capacity (in MW's) | MW					3,003
Virginia Electric and Power Company | Bath County, Virginia
Regulatory Assets [Line Items]
Proportionate ownership share					60.00%
AGC | Bath County, Virginia
Regulatory Assets [Line Items]
Plant generation capacity (in MW's) | MW					487
Proportionate ownership share					16.25%
Property, plant and equipment					$ 161,000,000
Global Holding
Regulatory Assets [Line Items]
Equity method investments					$ 28,000,000
Purchase Agreement with Subsidiary of LS Power
Regulatory Assets [Line Items]
Plant generation capacity (in MW's) | MW													1,615
Purchase Agreement with Subsidiary of LS Power | Pleasants Power Station | AE Supply
Regulatory Assets [Line Items]
Plant generation capacity (in MW's) | MW					1,300
Accounting Standards Update 2016-02
Regulatory Assets [Line Items]
Assets										$ 186,000,000
Liabilities										$ 186,000,000
Retained Earnings (Accumulated Deficit)
Regulatory Assets [Line Items]
Impact of adopting new accounting pronouncements				35,000,000		35,000,000	(6,000,000)
Line of Credit | Term Loan Facility Due March 2020 | Global Holding
Regulatory Assets [Line Items]
Face amount of loan					$ 120,000,000
Line of Credit | Secured Credit Facility | FES
Regulatory Assets [Line Items]
Maximum amount borrowed under revolving credit facility											500,000,000
Line of Credit | Credit Agreement | FES
Regulatory Assets [Line Items]
Maximum amount borrowed under revolving credit facility											200,000,000
Discontinued Operations, Disposed of by Means Other than Sale | FES and FENOC
Regulatory Assets [Line Items]
Investments in subsidiaries					0							$ 0
Amount of damages awarded to other party						66,000,000
Income taxes paid					14,000,000
Income (loss) from discontinued operations, before tax					(4,000,000)	(48,000,000)	$ (2,255,000,000)
Discontinued Operations, Disposed of by Means Other than Sale | FES and FENOC | Forecast
Regulatory Assets [Line Items]
Amount of damages awarded to other party	$ 83,000,000
Phase In Recovery Bonds
Regulatory Assets [Line Items]
Long-term debt and other long-term obligations				292,000,000	268,000,000	292,000,000
Phase In Recovery Bonds | Ohio Funding Companies
Regulatory Assets [Line Items]
Face amount of loan														$ 445,000,000
Senior Secured Term Loan | Senior Loans | Global Holding
Regulatory Assets [Line Items]
Long-term debt and other long-term obligations					114,000,000
Intercompany Income Tax Allocation Agreement | Loans Payable | FES
Regulatory Assets [Line Items]
Face amount of loan											628,000,000
Obligations settled in cash								$ 628,000,000
Affiliated companies | Benefit Obligations | Discontinued Operations, Disposed of by Means Other than Sale | FES and FENOC
Regulatory Assets [Line Items]
Obligations settled in cash									$ 60,000,000
Total obligations to be settled									$ 87,000,000
Income (loss) from discontinued operations, before tax			$ 27,000,000
Affiliated companies | Services Agreements | Discontinued Operations, Disposed of by Means Other than Sale | FES and FENOC | FES
Regulatory Assets [Line Items]
Amounts of transaction				$ 112,500,000	152,000,000
Affiliated companies | Pension Plan Enhancement | Discontinued Operations, Disposed of by Means Other than Sale | FES and FENOC
Regulatory Assets [Line Items]
Amounts of transaction					14,000,000
2017 | Discontinued Operations, Disposed of by Means Other than Sale | FES and FENOC
Regulatory Assets [Line Items]
Overpayment of NOL's reversed											71,000,000
2018 | Discontinued Operations, Disposed of by Means Other than Sale | FES and FENOC
Regulatory Assets [Line Items]
Overpayment of NOL's reversed											$ 88,000,000
Income taxes paid		$ 31,000,000
Path-WV
Regulatory Assets [Line Items]
Equity method investments					$ 18,000,000
Percentage of high-voltage transmission line project owned by subsidiary of FE on the Allegheny Series					100.00%
Percentage of high-voltage transmission line project owned by subsidiary of AE on the West Virginia Series					50.00%
Power Purchase Agreements
Regulatory Assets [Line Items]
Number of long term power purchase agreements maintained by parent company with Non utility generation entities | agreement					10
Ownership interest					0.00%
Power Purchase Agreements | Other FE subsidiaries
Regulatory Assets [Line Items]
Purchased power					$ 116,000,000	$ 108,000,000
Continuing Operations | Affiliated companies | Benefit Obligations | Discontinued Operations, Disposed of by Means Other than Sale | FES and FENOC
Regulatory Assets [Line Items]
Income (loss) from discontinued operations, before tax			$ 17,000,000
Signal Peak [Member] | Global Holding | FEV
Regulatory Assets [Line Items]
Ownership interest					33.33%