Commitments and Contingencies (Insurance) (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)
Insurance [Abstract]
Maximum obtainable amount of private liability insurance available under Price-Anderson Act	$ 450
Amount of secondary financial protection liability insurance coverage per incident	13,500
Potential retrospective assessments under secondary financial protection system	1,100
Potential retrospective assessments under secondary financial protection system payable per incident per year	164
Amount of coverage per occurrence per site for property damage, decontamination and premature decommissioning risks	2,750
Amount of sublimit for nonnuclear perils per occurrence per site under nuclear insurance mutual companies for property damage decontamination and premature decommissioning risks	$ 1,500
Coinsurance, percent	10.00%
Coinsurance, limit of coverage per loss per site occurrence	$ 400
Potential amount of retrospective assessment per occurrence per site for property damage, decontamination and premature decommissioning risks	174
FPL [Member]
Insurance [Abstract]
Potential retrospective assessments under secondary financial protection system	550
Potential retrospective assessments under secondary financial protection system payable per incident per year	82
Potential amount of retrospective assessment per occurrence per site for property damage, decontamination and premature decommissioning risks	106
Duane Arnold Energy Center Insurance [Member]
Insurance [Abstract]
Amount of sublimit for nonnuclear perils per occurrence per site under nuclear insurance mutual companies for property damage decontamination and premature decommissioning risks	500
Seabrook Station Insurance [Member]
Insurance [Abstract]
Potential retrospective assessment recoverable from minority interest for nuclear liability secondary financial protection	16
Potential retrospective assessment recoverable from minority interest for property damage, decontamination and premature decommissioning risks	3
Duane Arnold Energy Center Insurance [Member]
Insurance [Abstract]
Potential retrospective assessment recoverable from minority interest for nuclear liability secondary financial protection	41
Potential retrospective assessment recoverable from minority interest for property damage, decontamination and premature decommissioning risks	4
St Lucie Unit No 2 Insurance [Member]
Insurance [Abstract]
Potential retrospective assessment recoverable from minority interest for nuclear liability secondary financial protection	20
Potential retrospective assessment recoverable from minority interest for property damage, decontamination and premature decommissioning risks	$ 4