Derivative Instruments (Balance Sheet Disclosure) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Asset	$ 1,988	$ 2,235
Derivative Liability	771	881
Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	442	885
Derivative Asset, Collateral, Obligation to Return Cash, Offset	74	96
Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	1,546	1,350
Derivative Asset, Collateral, Obligation to Return Cash, Offset	12	71
Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	257	404
Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	514	477
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	33
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4,157	4,879
Derivative Liability, Fair Value, Gross Liability	2,887	3,358
Derivative Asset	1,988	2,235
Derivative Liability	771	881
Commodity Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4,081	4,590
Derivative Liability, Fair Value, Gross Liability	2,546	2,968
Derivative Asset	1,885	1,938
Derivative Liability	403	483
Interest Rate Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	76	288
Derivative Liability, Fair Value, Gross Liability	299	284
Derivative Asset	92	296
Derivative Liability	315	292
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0	1
Derivative Liability, Fair Value, Gross Liability	42	106
Derivative Asset	11	1
Derivative Liability	53	106
FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	7	209
Derivative Liability	3	1
FPL [Member] \| Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	7	209
FPL [Member] \| Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	3	1
FPL [Member] \| Commodity Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	11	212
Derivative Liability, Fair Value, Gross Liability	7	4
Derivative Asset	7	209
Derivative Liability	$ 3	$ 1

Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

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-Publisher FASB
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