Commitments and Contingencies (Insurance and Legal Proceedings) (Details) (USD $)	3 Months Ended	24 Months Ended
	Mar. 31, 2015	Dec. 31, 1996	Jan. 29, 1999
Insurance [Abstract]
Maximum obtainable amount of private liability insurance available under Price-Anderson Act	$ 375,000,000
Amount of secondary financial protection liability insurance coverage per incident	13,200,000,000
Potential Retrospective Assessments Under Secondary Financial Protection System	1,000,000,000
Potential Retrospective Assessments Under Secondary Financial Protection System Payable Per Incident Per Year	152,000,000
Amount of coverage per occurrence per site for property damage, decontamination and premature decommissioning risks	2,750,000,000
Amount of sublimit for nonnuclear perils per occurrence per site under nuclear inusurance mutal companies for property damage decontamination and premature decommissioning risks	1,500,000,000
Potential amount of retrospective assessment per occurrence per site for property damage, decontamination and premature decommissioning risks	187,000,000
Legal Proceedings [Abstract]
FPL's interest owned in generation facility Scherer Unit No. 4	76.00%
Maximum amount of civil penalties per day - Clean Air Act from June 1, 1975 through January 30, 1997	25,000
Maximum amount of civil penalties per day - Clean Air Act from January 31, 1997 through March 15, 2004	27,500
Maximum amount of civil penalties per day - Clean Air Act from March 16, 2004 through January 12, 2009	32,500
Maximum amount of civil penalties per day - Clean Air Act from January 13, 2009 forward	37,500
Shares of Adelphia common stock purchased (in shares)		1,091,524
Shares of Adelphia preferred stock purchased (in shares)		20,000
Shares of Adelphia common stock if Adelphia preferred stock converted to Adelphia common stock (in shares)		2,358,490
Aggregate price paid for Adelphia common and preferred stock		35,900,000
Cash paid by Adelphia for repurchase of Adelphia acquired shares			149,213,130
Seabrook Station Insurance [Member]
Insurance [Abstract]
Potential retrospective assessment recoverable from minority interest for nuclear liability secondary financial protection	15,000,000
Potential retrospective assessment recoverable from minority interest for property damage, decontamination and premature decommissioning risks	3,000,000
Duane Arnold Energy Center Insurance [Member]
Insurance [Abstract]
Potential retrospective assessment recoverable from minority interest for nuclear liability secondary financial protection	38,000,000
Potential retrospective assessment recoverable from minority interest for property damage, decontamination and premature decommissioning risks	5,000,000
St Lucie Unit No 2 Insurance [Member]
Insurance [Abstract]
Potential retrospective assessment recoverable from minority interest for nuclear liability secondary financial protection	19,000,000
Potential retrospective assessment recoverable from minority interest for property damage, decontamination and premature decommissioning risks	4,000,000
FPL [Member]
Insurance [Abstract]
Potential Retrospective Assessments Under Secondary Financial Protection System	509,000,000
Potential Retrospective Assessments Under Secondary Financial Protection System Payable Per Incident Per Year	76,000,000
Potential amount of retrospective assessment per occurrence per site for property damage, decontamination and premature decommissioning risks	$ 112,000,000