Fair Value Measurements, Reconciliation of Changes in the Fair Value of Derivatives (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Realized and unrealized gains (losses): [Abstract]
Realized and unrealized gains (losses) reflected in operating revenues	$ 228		$ (92)
Unrealized gains (losses) reflected in operating revenues	219		(86)
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	486		296
Realized and unrealized gains (losses): [Abstract]
Included in Earnings	231	[1]	(82)	[1]
Included in regulatory assets and liabilities	4		0
Purchases	158		88
Settlements	(124)	[2]	(45)	[2]
Issuances	(177)		(152)
Transfers in	16	[3]	1	[3]
Transfers out	(5)	[3]	(2)	[3]
Fair value of net derivatives based on significant unobservable inputs, ending balance	589		104
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	$ 221		$ (80)

[1] For the three months ended March 31, 2012 and 2011, $228 million and $(92) 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 three months ended March 31, 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.

[3] For the three months ended March 31, 2012 and 2011, $219 million and $(86) 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.