Derivative Instruments (Balance Sheet Disclosure) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Asset	$ 2,140	$ 2,235
Derivative Liability	803	881
Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	678	885
Derivative Asset, Collateral, Obligation to Return Cash, Offset	158	96
Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	1,462	1,350
Derivative Asset, Collateral, Obligation to Return Cash, Offset	70	71
Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	330	404
Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	473	477
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4,798	4,879
Derivative Liability, Fair Value, Gross Liability	3,233	3,358
Derivative Asset	2,140	2,235
Derivative Liability	803	881
FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	82	209
Derivative Liability	5	1
FPL [Member] \| Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	82	209
FPL [Member] \| Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	4	1
FPL [Member] \| Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	1
Commodity Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4,539	4,590
Derivative Liability, Fair Value, Gross Liability	2,863	2,968
Derivative Asset	1,877	1,938
Derivative Liability	429	483
Commodity Contract [Member] \| FPL [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	84	212
Derivative Liability, Fair Value, Gross Liability	7	4
Derivative Asset	82	209
Derivative Liability	5	1
Interest Rate Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	258	288
Derivative Liability, Fair Value, Gross Liability	290	284
Derivative Asset	262	296
Derivative Liability	294	292
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1	1
Derivative Liability, Fair Value, Gross Liability	80	106
Derivative Asset	1	1
Derivative Liability	$ 80	$ 106

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

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-Publisher FASB
-Name Accounting Standards Codification
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