Derivative Instruments (Balance Sheet Disclosure) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Derivatives, Fair Value [Line Items]
Derivative Asset	$ 1,974	$ 2,235
Derivative Liability	784	881
Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	546	885
Derivative Asset, Collateral, Obligation to Return Cash, Offset	125	96
Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	1,428	1,350
Derivative Asset, Collateral, Obligation to Return Cash, Offset	16	71
Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	277	404
Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	507	477
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4,563	4,879
Derivative Liability, Fair Value, Gross Liability	3,232	3,358
Derivative Asset	1,974	2,235
Derivative Liability	784	881
Commodity Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4,409	4,590
Derivative Liability, Fair Value, Gross Liability	2,883	2,968
Derivative Asset	1,814	1,938
Derivative Liability	429	483
Interest Rate Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	154	288
Derivative Liability, Fair Value, Gross Liability	306	284
Derivative Asset	152	296
Derivative Liability	304	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	43	106
Derivative Asset	8	1
Derivative Liability	51	106
FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	18	209
Derivative Liability	2	1
FPL [Member] \| Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	18	209
FPL [Member] \| Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	2	1
FPL [Member] \| Commodity Contract [Member] \| Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	27	212
Derivative Liability, Fair Value, Gross Liability	11	4
Derivative Asset	18	209
Derivative Liability	$ 2	$ 1

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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