Derivative Instruments (Balance Sheet Disclosure) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 4,102		$ 4,232
Derivative Liability, Fair Value, Gross Liability	3,155		3,345
Not Designated as Hedging Instrument [Member] | Commodity contracts [Member] | Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	862		851
Derivative Liability, Fair Value, Gross Liability	373		321
Not Designated as Hedging Instrument [Member] | Commodity contracts [Member] | Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,331		1,441
Derivative Liability, Fair Value, Gross Liability	1,598		1,838
Not Designated as Hedging Instrument [Member] | Commodity contracts [Member] | Non Current Other Assets Member
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,682		1,748
Derivative Liability, Fair Value, Gross Liability	693		715
Not Designated as Hedging Instrument [Member] | Commodity contracts [Member] | Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	227		192
Derivative Liability, Fair Value, Gross Liability	426		438
Not Designated as Hedging Instrument [Member] | Foreign currency swaps [Member] | Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	4		3
Not Designated as Hedging Instrument [Member] | Foreign currency swaps [Member] | Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	61		30
Derivatives designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	73		76
Derivative Liability, Fair Value, Gross Liability	322		420
Derivatives designated as hedging instruments [Member] | Interest Rate Contract [Member] | Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	30		30
Derivative Liability, Fair Value, Gross Liability	0		0
Derivatives designated as hedging instruments [Member] | Interest Rate Contract [Member] | Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	187		104
Derivatives designated as hedging instruments [Member] | Interest Rate Contract [Member] | Non Current Other Assets Member
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	43		46
Derivative Liability, Fair Value, Gross Liability	0		0
Derivatives designated as hedging instruments [Member] | Interest Rate Contract [Member] | Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	97		283
Derivatives designated as hedging instruments [Member] | Foreign currency swaps [Member] | Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	4		5
Derivatives designated as hedging instruments [Member] | Foreign currency swaps [Member] | Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	34		28
FPL [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	146		17
Derivative Liability, Fair Value, Gross Liability	2		32
FPL [Member] | Not Designated as Hedging Instrument [Member] | Commodity contracts [Member] | Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	137	[1]	4	[1]
Derivative Liability, Fair Value, Gross Liability	1	[1]	0
FPL [Member] | Not Designated as Hedging Instrument [Member] | Commodity contracts [Member] | Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		12	[2]
Derivative Liability, Fair Value, Gross Liability	1	[2]	32	[2]
FPL [Member] | Not Designated as Hedging Instrument [Member] | Commodity contracts [Member] | Non Current Other Assets Member
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	9	[3]	1	[3]
Derivative Liability, Fair Value, Gross Liability	0		0
FPL [Member] | Not Designated as Hedging Instrument [Member] | Commodity contracts [Member] | Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	0		0
FPL [Member] | Not Designated as Hedging Instrument [Member] | Foreign currency swaps [Member] | Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	0		0
FPL [Member] | Not Designated as Hedging Instrument [Member] | Foreign currency swaps [Member] | Noncurrent derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	$ 0		$ 0

[1] Included in current other assets on FPL's condensed consolidated balance sheets.

[2] Included in current other liabilities on FPL's condensed consolidated balance sheets.

[3] Included in noncurrent other assets on FPL's condensed consolidated balance sheets.