Fair Value Measurements (Reconciliation of Change in Fair Value of Derivatives, Significant Unobservable Inputs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Realized and unrealized gains (losses):
Realized and unrealized gains (losses) reflected in operating revenues	$ 302		$ 220		$ 441
Unrealized gains (losses) reflected in operating revenues, for derivatives still held at the reporting date	330		157		423
Derivative Financial Instruments, Net [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of derivatives based on significant unobservable inputs beginning balance	566		486		296
Realized and unrealized gains (losses):
Realized and unrealized gains (losses) included in earnings	299	[1]	218	[1]	454	[1]
Realized and unrealized gains (losses) included in regulatory assets and liabilities	0		5		3
Purchases	101		273		270
Settlements	(55)		(181)		(166)
Issuances	(173)		(243)		(362)
Transfers in(b)	(120)	[2]	20	[2]	6	[2]
Transfers out(b)	4	[2]	(12)	[2]	(15)	[2]
Fair value of derivatives based on significant unobservable inputs ending balance	622		566		486
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(c)	329	[3]	152	[3]	423	[3]
FPL [Member] | Derivative Financial Instruments, Net [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Fair value of derivatives based on significant unobservable inputs beginning balance	2		4		7
Realized and unrealized gains (losses):
Realized and unrealized gains (losses) included in earnings	0		0		0
Realized and unrealized gains (losses) included in regulatory assets and liabilities	0		5		3
Purchases	0		(7)		(6)
Settlements	(2)		0		0
Issuances	0		0		0
Transfers in(b)	0		0		0
Transfers out(b)	0		0		0
Fair value of derivatives based on significant unobservable inputs ending balance	0		2		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(c)	$ 0		$ 0		$ 0

[1] For the year ended December 31, 2013, $302 million of realized and unrealized gains are reflected in the consolidated statement of income in operating revenues and the balance is primarily reflected in interest expense. For the years ended December 31, 2012 and 2011, $220 million and $441 million, respectively, of realized and unrealized gains are reflected in the consolidated statements of income in operating revenues and the balance is reflected in fuel, purchased power and interchange.

[2] Transfers into Level 3 were a result of decreased observability of market data and, in 2013, the use of a significant credit valuation adjustment. 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 year ended December 31, 2013, $330 million of unrealized gains are reflected in the consolidated statements of income in operating revenues and the balance is reflected in interest expense. For the years ended December 31, 2012 and 2011, $157 million and $423 million, respectively, of unrealized gains are reflected in the consolidated statements of income in operating revenues and the balance is reflected in fuel, purchased power and interchange.