Derivative Instruments (Net Notional Volumes and Additional Disclosures) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014 MWh		Dec. 31, 2013 MWh
Power [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes	(73,000,000)	[1]	(276,000,000)	[1]
Natural Gas [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes	1,436,000,000	[2]	1,140,000,000	[2]
Oil [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes	(11,000,000)		(10,000,000)
Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount of Foreign Currency Cash Flow Hedge Derivatives	7,400		6,500
Currency Swap [Member]
Derivative [Line Items]
Notional Amount of Foreign Currency Cash Flow Hedge Derivatives	661		662
FPL [Member] | Commodity contract - Power [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes	0		0
FPL [Member] | Commodity contract - Natural gas [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes	845,000,000	[2]	674,000,000	[2]
FPL [Member] | Commodity contract - Oil [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes	0		0

[1] Megawatt-hours

[2] One million British thermal units