REGULATORY MATTERS - Pennsylvania and West Virginia (Details)																	3 Months Ended		9 Months Ended
	Sep. 13, 2024 USD ($)	Jul. 22, 2024 USD ($)	Apr. 02, 2024 USD ($)	Mar. 26, 2024 USD ($)	Jan. 23, 2024 USD ($)	Dec. 08, 2023 auditMatter	Nov. 30, 2023 USD ($)	Aug. 31, 2023 USD ($)	Aug. 22, 2023 USD ($)	May 31, 2023 USD ($)	Apr. 24, 2023 MW	Jan. 13, 2023 USD ($)	May 01, 2022 MW	Feb. 24, 2022	Nov. 22, 2021 site	Jan. 16, 2020 USD ($)	Mar. 31, 2024 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2024 USD ($)
Transmission Related Vegetation Management Programs | FERC | FE
Regulatory Matters [Line Items]
Customer refund																		$ 45,000,000
Customer refund, net																		34,000,000
Capital assets																		195,000,000
Operating expense																		90,000,000
Operating expense, net																		67,000,000
Utilities reclassification to operating expense																		$ 105,000,000
Amount of costs recovered																			$ 85,000,000
Reduction in operating expense																			160,000,000
Utilities cooperate support																			200,000,000
Public utilities, number of unresolved audit matters | auditMatter						2
Utilities, transmission owning utilities join an RTO														0.00500000
Pennsylvania | EE&C Phase IV | PPUC
Regulatory Matters [Line Items]
Public utilities, approved energy consumption reduction targets, cost recovery																			$ 390,000,000
Pennsylvania | EE&C Phase IV | PPUC | ME
Regulatory Matters [Line Items]
Demand reduction targets																			2.90%
Energy consumption reduction targets																			3.10%
Pennsylvania | EE&C Phase IV | PPUC | PN
Regulatory Matters [Line Items]
Demand reduction targets																			3.30%
Energy consumption reduction targets																			3.00%
Pennsylvania | EE&C Phase IV | PPUC | Penn
Regulatory Matters [Line Items]
Demand reduction targets																			2.00%
Energy consumption reduction targets																			2.70%
Pennsylvania | EE&C Phase IV | PPUC | WP
Regulatory Matters [Line Items]
Demand reduction targets																			2.50%
Energy consumption reduction targets																			2.40%
Pennsylvania | New LTIIPs | PPUC | Pennsylvania Companies
Regulatory Matters [Line Items]
Recovery period																5 years
Approved total capital investments																$ 572,000,000
Proposed investment amount		$ 1,600,000,000
Pennsylvania | 2025-2029 LTIIP | PPUC | Pennsylvania Companies
Regulatory Matters [Line Items]
Proposed investment amount		$ 1,400,000,000
Pennsylvania | Energy Efficiency and Peak Demand Reduction Stipulation Settlement | PPUC | FE PA | Distribution Segment
Regulatory Matters [Line Items]
Increase base distribution rate			$ 502,000,000
Approved ROE			11.30%
Capital structure, debt			46.20%
Capital structure, equity			53.80%
Public utilities, net average rate increase, percentage			0.077
Public utilities, residential rate increase, percentage			0.105
Pennsylvania | Enhanced Vegetation Management Program | PPUC | FE PA | Distribution Segment
Regulatory Matters [Line Items]
Recovery period			10 years
Amount of requested rate increase	$ 225,000,000
West Virginia | WVPSC | MP and PE
Regulatory Matters [Line Items]
Amount of requested rate increase										$ 207,000,000
Approved amount of annual increase				$ 105,000,000	$ 105,000,000
Requested amount of annual depreciation expense										$ 75,000,000		$ 76,000,000
Increase in annual amount of depreciation expense					$ 33,000,000				$ 33,000,000
Pre tax benefit																	$ 60,000,000
West Virginia | WVPSC | MP and PE | Solar Generation Project
Regulatory Matters [Line Items]
Percent of subscriptions required prior to commencement of construction													85.00%
Plant capacity (in MW's) | MW											30		50
Expected cost of the program																			$ 110,000,000
Number of approved solar sites | site															3
West Virginia | ENEC | WVPSC | MP and PE
Regulatory Matters [Line Items]
Amount of requested rate increase								$ 167,500,000
Under recovered amount, percent								9.90%
Public utilities, deferred requested rate Increase amount								$ 92,000,000
Supplemental requested decrease								267,000,000
Public utilities, requested under recovery, not recovered, amount								$ 75,600,000
Carrying charge, percent								0.04
Approved amount of annual increase							$ 55,400,000
Recovery amounts							50,000,000
West Virginia | Expanded Net Energy Cost Through 2026 | WVPSC | MP and PE
Regulatory Matters [Line Items]
Approved amount of annual increase							$ 184,000,000