Derivative Instruments (Balance Sheet Disclosure) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative assets	$ 2,229	$ 1,919
Derivative Asset, Current	580	564
Derivative Asset, Noncurrent	1,649	1,355
Derivative liability	1,472	1,191
Derivative Liability, Current	239	675
Derivative Liability, Noncurrent	1,233	516
Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	2	124
Current derivative liabilities [Member] [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	6
Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	61	65
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	4,463	4,724
Derivative liability, fair value, gross liability	3,649	3,807
Derivative assets	2,229	1,919
Derivative liability	1,472	1,191
Commodity Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	4,416	4,651
Derivative liability, fair value, gross liability	2,651	3,305
Derivative assets	2,203	1,840
Derivative liability	495	683
Interest Rate Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	27	56
Derivative liability, fair value, gross liability	956	472
Derivative assets	6	49
Derivative liability	935	465
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	20	17
Derivative liability, fair value, gross liability	42	30
Derivative assets	20	30
Derivative liability	42	43
FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	7	0
Derivative liability	16	41
FPL [Member] \| Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	7
FPL [Member] \| Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current	14	32
FPL [Member] \| Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability		9
Derivative Liability, Noncurrent	2
FPL [Member] \| Commodity Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	10	2
Derivative liability, fair value, gross liability	19	43
Derivative assets	7	0
Derivative liability	$ 16	$ 41

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