Derivative Instruments (Net Notional Volumes and Additional Disclosures) (Details) bbl in Millions, MWh in Millions, MMBTU in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) MWh MMBTU bbl	Dec. 31, 2017 USD ($) MWh MMBTU bbl
Interest Rate Swap [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Notional Amount of Foreign Currency Cash Flow Hedge Derivatives | $	$ 18,200	$ 12,100
Currency Swap [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Notional Amount of Foreign Currency Cash Flow Hedge Derivatives | $	$ 656	$ 718
Short [Member] | Commodity contract - Power [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes | MWh	100	109
Short [Member] | Commodity contract - Natural gas [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	491	74
Short [Member] | Commodity contract - Oil [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Derivative, Nonmonetary Notional Amount, Volume | bbl	30	15
Short [Member] | FPL[Member] | Commodity contract - Oil [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Derivative, Nonmonetary Notional Amount, Volume | bbl	0	0
Long [Member] | FPL[Member] | Commodity contract - Power [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Non monetary net notional volumes | MWh	1	0
Long [Member] | FPL[Member] | Commodity contract - Natural gas [Member]
Schedule of net notional volume of commodity derivative instruments [Abstract]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	231	142