Derivative Instruments (Net Notional Volumes and Additional Disclosures) (Details) bbl in Millions, MWh in Millions, MMBTU in Millions, $ in Millions	Jun. 30, 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	(75)	(112)
Commodity contract - Natural gas [Member]
Derivative [Line Items]
Non-monetary net notional volumes | MMBTU	1,408	1,321
Commodity contract - Oil [Member]
Derivative [Line Items]
Non-monetary net notional volumes | bbl	(9)	(9)
Currency Swap [Member]
Derivative [Line Items]
Notional amount | $	$ 705	$ 715
Interest Rate Contract [Member]
Derivative [Line Items]
Notional amount | $	$ 13,700	$ 8,300
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	789	833
FPL [Member] | Commodity contract - Oil [Member]
Derivative [Line Items]
Non-monetary net notional volumes | bbl	0	0