Derivative Instruments (Balance Sheet Disclosure) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 3,836		$ 4,232
Derivative Liability, Fair Value, Gross Liability	3,085		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	689		851
Derivative Liability, Fair Value, Gross Liability	203		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	1,113		1,441
Derivative Liability, Fair Value, Gross Liability	1,489		1,838
Not Designated as Hedging Instrument [Member] | Commodity contracts [Member] | Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1,798		1,748
Derivative Liability, Fair Value, Gross Liability	717		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	235		192
Derivative Liability, Fair Value, Gross Liability	505		438
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	1		0
Derivative Liability, Fair Value, Gross Liability	0		0
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	91		0
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	80		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	0		30
Derivatives designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	77		76
Derivative Liability, Fair Value, Gross Liability	167		420
Derivatives designated as hedging instruments [Member] | Interest Rate Contracts [Member] | Current derivative assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	29		30
Derivative Liability, Fair Value, Gross Liability	0		0
Derivatives designated as hedging instruments [Member] | Interest Rate Contracts [Member] | Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		0
Derivative Liability, Fair Value, Gross Liability	62		104
Derivatives designated as hedging instruments [Member] | Interest Rate Contracts [Member] | Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	48		46
Derivative Liability, Fair Value, Gross Liability	0		0
Derivatives designated as hedging instruments [Member] | Interest Rate 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	68		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	21		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	16		28
FPL [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	9		17
Derivative Liability, Fair Value, Gross Liability	70		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	2	[1]	4	[1]
Derivative Liability, Fair Value, Gross Liability	0		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	6	[2]	12	[2]
Derivative Liability, Fair Value, Gross Liability	61	[2]	32	[2]
FPL [Member] | Not Designated as Hedging Instrument [Member] | Commodity contracts [Member] | Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	0		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	1	[4]	0
Derivative Liability, Fair Value, Gross Liability	9	[4]	0
FPL [Member] | Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member] | Current derivative assets [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] | Interest Rate Contracts [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] | 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.

[4] Included in noncurrent other liabilities on FPL's condensed consolidated balance sheets.