Derivative Instruments (Balance Sheet Disclosure) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivative assets	$ 2,431	$ 1,919
Derivative Asset, Current	805	564
Derivative Asset, Noncurrent	1,626	1,355
Derivative liability	1,235	1,191
Derivative Liability, Current	343	675
Derivative Liability, Noncurrent	892	516
Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	8	124
Current derivative liabilities [Member] [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	177
Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	43
Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral		65
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	5,189	4,724
Derivative liability, fair value, gross liability	4,205	3,807
Derivative assets	2,431	1,919
Derivative liability	1,235	1,191
Commodity Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	5,152	4,651
Derivative liability, fair value, gross liability	3,594	3,305
Derivative assets	2,399	1,840
Derivative liability	629	683
Interest Rate Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	14	56
Derivative liability, fair value, gross liability	574	472
Derivative assets	9	49
Derivative liability	569	465
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	23	17
Derivative liability, fair value, gross liability	37	30
Derivative assets	23	30
Derivative liability	37	43
FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	6	0
Derivative liability	17	41
FPL [Member] \| Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	6
FPL [Member] \| Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current	13	32
FPL [Member] \| Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative liability		9
Derivative Liability, Noncurrent	4
FPL [Member] \| Commodity Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative asset, fair value, gross asset	8	2
Derivative liability, fair value, gross liability	19	43
Derivative assets	6	0
Derivative liability	$ 17	$ 41

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