Regulatory Matters - Maryland and New Jersey (Details) $ in Millions									12 Months Ended	36 Months Ended
	Apr. 23, 2019 USD ($)	Mar. 22, 2019 USD ($)	Oct. 22, 2018 USD ($)	Aug. 24, 2018 USD ($) program	Jul. 13, 2018 USD ($)	Mar. 02, 2018 USD ($)	Jan. 19, 2018 USD ($)	Jul. 16, 2015	Dec. 31, 2019	Dec. 31, 2020 USD ($)
PE | MDPSC
Regulatory Matters [Line Items]
Cost of charging equipment rebates							$ 12.0
Charging equipment rebates amortization period							5 years
PE | Maryland
Regulatory Matters [Line Items]
Incremental energy savings goal per year (percent)								0.20%
Incremental energy savings goal thereafter (percent)								2.00%
Amortization period for expenditures for cost recovery program									5 years
PE | Maryland | MDPSC
Regulatory Matters [Line Items]
Requested increase (decrease) in revenues		$ 6.2
Requested rate increase (decrease)				$ 19.7
Number of enhanced service reliability programs | program				4,000,000
Revised requested rate increase			$ 17.6
Revised rate increase				$ 7.3
JCP&L | New Jersey | NJBPU
Regulatory Matters [Line Items]
Requested increase (decrease) in revenues	$ 28.6					$ (28.6)
Approved rate increase due to changes in deferred taxes						$ 1.3
Amount of approved rate refund	7.0
Forecast | PE | Maryland
Regulatory Matters [Line Items]
Recovery period for expenditures for cost recovery program										3 years
Expenditures for cost recovery program										$ 116.0
JCP&L Reliability Plus | JCP&L | NJBPU
Regulatory Matters [Line Items]
Requested rate increase (decrease)					$ 386.8
JCP&L Reliability Plus | JCP&L | New Jersey | NJBPU
Regulatory Matters [Line Items]
Requested increase (decrease) in revenues	$ 97.0
Infrastructure investment period					4 years