REGULATORY MATTERS - Maryland and New Jersey (Details) meter in Millions, $ in Millions													10 Months Ended	12 Months Ended			36 Months Ended
	Sep. 14, 2021 USD ($)	May 26, 2021 USD ($)	Apr. 23, 2021 USD ($)	Mar. 05, 2021 USD ($)	Mar. 01, 2021 USD ($) program	Oct. 28, 2020 USD ($) MW	Sep. 25, 2020 program	Aug. 27, 2020 USD ($) meter	Jun. 10, 2020	Apr. 06, 2020 USD ($)	Mar. 22, 2019	Jul. 16, 2015	Oct. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) MW	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) program	Dec. 31, 2020 USD ($)
Regulatory Matters [Line Items]
Gain on sale of property														$ 109.0	$ 0.0	$ 0.0
Regulated Distribution
Regulatory Matters [Line Items]
Plant generation capacity (in MW's) | MW														3,580
PE | Maryland
Regulatory Matters [Line Items]
Incremental energy savings goal per year (percent)												0.20%
Incremental energy savings goal thereafter (percent)												2.00%
PE | Maryland | MDPSC
Regulatory Matters [Line Items]
Requested increase (decrease) in revenues																$ 6.2
Number of approved ESR programs | program																3
ESR program term																4 years
Period to file new depreciation study																18 months
ESER Program rate case renewal period											4 years
JCP&L | New Jersey | Yard's Creek Energy, LLC Hydro Generation Facility
Regulatory Matters [Line Items]
Plant generation capacity (in MW's) | MW						210
Consideration transferred										$ 155.0
JCP&L | New Jersey | Yard's Creek Energy, LLC Hydro Generation Facility | Regulated Distribution
Regulatory Matters [Line Items]
Assets acquired														$ 45.0
Gain on sale of property				$ 109.0
JCP&L | New Jersey | NJBPU
Regulatory Matters [Line Items]
Settled amount of increase in revenue						$ 94.0
Requested ROE						9.60%
Settled decrease in regulatory liability													$ 86.0
JCP&L | New Jersey | NJBPU | Yard's Creek Energy, LLC Hydro Generation Facility
Regulatory Matters [Line Items]
Ownership interest acquired										50.00%
JCP&L Reliability Plus | JCP&L | New Jersey | NJBPU
Regulatory Matters [Line Items]
Approved amount included in rate base															$ 95.0		$ 95.0
2021-2023 EmPOWER Program Cycle | PE | Maryland
Regulatory Matters [Line Items]
Expenditures for cost recovery program																	$ 148.0
Recovery period for expenditures for cost recovery program																	3 years
Amortization period for expenditures for cost recovery program														5 years
Advanced metering infrastructure | JCP&L | New Jersey | Regulated Distribution
Regulatory Matters [Line Items]
Requested rate increase (decrease)								$ (732.0)
Advanced metering infrastructure | JCP&L | New Jersey | NJBPU | Regulated Distribution
Regulatory Matters [Line Items]
Number of meters to be deployed | meter								1.2
Deployment period								3 years
Expected cost of the program								$ 418.0
Meter deployment program period								20 years
Energy Efficiency and Peak Demand Reduction | JCP&L | New Jersey | NJBPU | Regulated Distribution
Regulatory Matters [Line Items]
Amortization period for expenditures for cost recovery program			10 years						10 years
Number of programs | program							11
Depreciation Study | PE | Maryland | Maryland Office of People's Counsel
Regulatory Matters [Line Items]
Requested increase (decrease) in revenues		$ (2.1)
Advanced Metering Infrastructure Supplemental Filing | JCP&L | New Jersey | Regulated Distribution
Regulatory Matters [Line Items]
Meter program period	6 years
Requested rate increase due to costs associated with program	$ 494.0
Requested increase due to capital expenditures	390.0
Requested increase due to maintenance expense	73.0
Cost of removal	$ 31.0
Energy Efficiency and Peak Demand Reduction Stipulation Settlement | JCP&L | New Jersey | NJBPU | Regulated Distribution
Regulatory Matters [Line Items]
Requested rate increase (decrease)			$ (203.0)
Approved rate plan period			3 years
Approved amount of investment recovery over amortization period			$ 158.0
Approved amount of operation costs and maintenance recovery			$ 45.0
Electrical Vehicle Program | JCP&L | New Jersey | NJBPU | Regulated Distribution
Regulatory Matters [Line Items]
Requested rate increase (decrease)					$ (50.0)
Number of programs | program					6
Electric vehicle program period					4 years
Requested ROE					$ 16.0
Apportioned for operations and maintenance expense amount					$ 34.0