Derivative Instruments (Balance Sheet Disclosure) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Derivative Asset	$ 1,471		$ 1,661
Derivative Liability	1,247		1,311
Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset	81		181
Derivative Asset	577	[1]	498	[2]
Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	1
Derivative Liability	686	[3]	838
Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Collateral, Obligation to Return Cash, Offset	68		98
Derivative Asset	894	[4]	1,163	[5]
Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	14
Derivative Liability	561	[6]	473
Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	1,400		1,571
Derivative Liability	974		940
Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	68		90
Derivative Liability	238		220
Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	3		0
Derivative Liability	35		151
FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	84		48
Derivative Liability	12		2
FPL [Member] | Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	81		48
FPL [Member] | Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	1		1
FPL [Member] | Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	3
FPL [Member] | Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	11		1
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	5,482		4,544
Derivative Liability, Fair Value, Gross Liability	5,041		3,827
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	43		89
Derivative Liability, Fair Value, Gross Liability	126		177
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	0		101
Foreign Exchange Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	32		50
Interest Rate 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	119		93
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	43		89
Derivative Liability, Fair Value, Gross Liability	94		127
Commodity Contract [Member] | FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	84		48
Derivative Liability	12		2
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	5,482		4,543
Derivative Liability, Fair Value, Gross Liability	4,922		3,633
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	84		55
Derivative Liability, Fair Value, Gross Liability	12		9
Commodity Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	0		0
Commodity Contract [Member] | Designated as Hedging Instrument [Member] | FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	$ 0		$ 0

[1] Reflects the netting of approximately $81 million in margin cash collateral received from counterparties.

[2] Reflects the netting of approximately $181 million in margin cash collateral received from counterpar

[3] Reflects the netting of approximately $1 million in margin cash collateral provided to counterparties.

[4] Reflects the netting of approximately $68 million in margin cash collateral received from counterparties.

[5] Reflects the netting of approximately $98 million in margin cash collateral received from counterpar

[6] Reflects the netting of approximately $14 million in margin cash collateral provided to counterparties.