Fair Value Measurements, Reconciliation of Changes in the Fair Value of Derivatives (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Realized and unrealized gains (losses): [Abstract]
Realized and unrealized gains (losses) reflected in operating revenues	$ (149)		$ (12)		$ 132		$ (11)
Unrealized gains (losses) reflected in operating revenues	(170)		12		41		37
Derivative Financial Instruments, Net [Member]
Reconciliation of changes in the fair value of derivatives measured based on significant unobservable inputs Roll Forward [Abstract]
Fair value of net derivatives based on significant unobservable inputs, beginning balance	575		155		486		296
Realized and unrealized gains (losses): [Abstract]
Included in Earnings	(149)	[1]	(11)	[1]	135	[2]	2	[2]
Included in regulatory assets and liabilities	1		0		7		2
Purchases	40		45		221		186
Settlements	30		3		(152)		(100)
Issuances	(21)		(70)		(221)		(260)
Transfers in	5	[3]	1	[3]	21	[4]	3	[4]
Transfers out	1	[3]	(2)	[3]	(15)	[4]	(8)	[4]
Fair value of net derivatives based on significant unobservable inputs, ending balance	482		121		482		121
The amount of gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to derivatives still held at the reporting date	(171)	[5]	12	[5]	41	[6]	42	[6]
FPL [Member] | Derivative Financial Instruments, Net [Member]
Reconciliation of changes in the fair value of derivatives measured based on significant unobservable inputs Roll Forward [Abstract]
Fair value of net derivatives based on significant unobservable inputs, beginning balance	7		5		4		7
Realized and unrealized gains (losses): [Abstract]
Included in Earnings	0		0		0		0
Included in regulatory assets and liabilities	1		0		7		2
Purchases	0		0		0		0
Settlements	(3)		(1)		(6)		(5)
Issuances	0		0		0		0
Transfers in	0		0		0		0
Transfers out	0		0		0		0
Fair value of net derivatives based on significant unobservable inputs, ending balance	5		4		5		4
The amount of gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to derivatives still held at the reporting date	$ 0		$ 0		$ 0		$ 0

[1] For the three months ended September 30, 2012 and 2011, $(149) million and $(12) million, respectively, of realized and unrealized gains (losses) are reflected in the condensed consolidated statements of income in operating revenues and the balance is reflected in fuel, purchased power and interchange.

[2] For the nine months ended September 30, 2012 and 2011, $132 million and $(11) million, respectively, of realized and unrealized gains (losses) are reflected in the condensed consolidated statements of income in operating revenues and the balance is reflected in fuel, purchased power and interchange.

[3] For the three months ended September 30, 2012 and 2011, transfers into Level 3 were a result of decreased observability of market data and transfers from Level 3 to Level 2 were a result of increased observability of market data. NEE's and FPL's policy is to recognize all transfers at the beginning of the reporting period.

[4] For the nine months ended September 30, 2012 and 2011, transfers into Level 3 were a result of decreased observability of market data and transfers from Level 3 to Level 2 were a result of increased observability of market data. NEE's and FPL's policy is to recognize all transfers at the beginning of the reporting period.

[5] For the three months ended September 30, 2012 and 2011, $(170) million and $12 million, respectively, of unrealized gains (losses) are reflected in the condensed consolidated statements of income in operating revenues

[6] For the nine months ended September 30, 2012 and 2011, $41 million and $37 million, respectively, of unrealized gains (losses) are reflected in the condensed consolidated statements of income in operating revenues and the balance is reflected in fuel, purchased power and interchange.