Derivative Instruments (Balance Sheet Disclosure) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Derivative Asset	$ 1,517		$ 1,661
Derivative Liability	1,211		1,311
Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	165		181
Derivative Asset	533	[1]	498	[2]
Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	815		838
Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	88		98
Derivative Asset	984	[3]	1,163	[4]
Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Amount Offset Against Collateral	12
Derivative Liability	396	[5]	473
Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	1,441		1,571
Derivative Liability	834		940
Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	76		90
Derivative Liability	233		220
Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	0		0
Derivative Liability	144		151
FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	130		48
Derivative Liability	10		2
FPL [Member] | Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	129		48
FPL [Member] | Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability			1
FPL [Member] | Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	1
FPL [Member] | Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability	10		1
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4,553		4,544
Derivative Liability, Fair Value, Gross Liability	3,908		3,827
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	76		89
Derivative Liability, Fair Value, Gross Liability	174		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	95		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	49		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	108		93
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	76		89
Derivative Liability, Fair Value, Gross Liability	125		127
Commodity Contract [Member] | FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset	130		48
Derivative Liability	10		2
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	4,553		4,543
Derivative Liability, Fair Value, Gross Liability	3,705		3,633
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	123		55
Derivative Liability, Fair Value, Gross Liability	3		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 $165 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 $88 million in margin cash collateral received from counterparties.

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

[5] Reflects the netting of approximately $12 million in margin cash collateral provided to counterparties.