Derivative Instruments (Net Notional Volumes and Additional Disclosures) (Details) bbl in Millions, MWh in Millions, MMBTU in Millions, $ in Millions	Dec. 31, 2016 USD ($) MWh MMBTU bbl	Dec. 31, 2015 USD ($) MWh MMBTU bbl
Derivative [Line Items]
Collateral Already Posted, Aggregate Fair Value	$ 1	$ 0
Commodity contract - Power [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes | MWh	84	112
Commodity contract - Natural gas [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes | MMBTU	1,002	1,321
Commodity contract - Oil [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes | bbl	7	9
Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount of Foreign Currency Cash Flow Hedge Derivatives	$ 15,100	$ 8,300
Currency Swap [Member]
Derivative [Line Items]
Notional Amount of Foreign Currency Cash Flow Hedge Derivatives	705	715
FPL [Member]
Derivative [Line Items]
Collateral Already Posted, Aggregate Fair Value	$ 0	$ 0
FPL [Member] | Commodity contract - Power [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes | MWh	0	0
FPL [Member] | Commodity contract - Natural gas [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes | MMBTU	618	833
FPL [Member] | Commodity contract - Oil [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes | bbl	0	0