Derivative Instruments (Net Notional Volumes and Additional Disclosures) (Details) bbl in Millions, MWh in Millions, MMBTU in Millions, $ in Millions	Mar. 31, 2016 USD ($) MWh MMBTU bbl	Dec. 31, 2015 USD ($) MWh MMBTU bbl
Commodity contract - Power [Member]
Derivative [Line Items]
Non-monetary net notional volumes | MWh	(113)	(112)
Commodity contract - Natural gas [Member]
Derivative [Line Items]
Non-monetary net notional volumes | MMBTU	1,611	1,321
Commodity contract - Oil [Member]
Derivative [Line Items]
Non-monetary net notional volumes | bbl	(9)	(9)
Interest rate contracts [Member]
Derivative [Line Items]
Notional amount | $	$ 8,200	$ 8,300
Currency Swap [Member]
Derivative [Line Items]
Notional amount | $	$ 700	$ 715
FPL [Member] | Commodity contract - Power [Member]
Derivative [Line Items]
Non-monetary net notional volumes | MWh	0	0
FPL [Member] | Commodity contract - Natural gas [Member]
Derivative [Line Items]
Non-monetary net notional volumes | MMBTU	915	833
FPL [Member] | Commodity contract - Oil [Member]
Derivative [Line Items]
Non-monetary net notional volumes | bbl	0	0