Regulatory Matters - Reliability and FERC Matters (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
FERC
Regulatory Matters [Line Items]
Denied recovery charges of exit fees	$ 78.8
JCP&L
Regulatory Matters [Line Items]
Approved ROE	9.60%
Approved capital structure	45.00%