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, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Realized and unrealized gains (losses): [Abstract]
Realized and unrealized gains (losses) reflected in operating revenues	$ 242		$ (149)		$ 244		$ 132
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Gain (Loss) Included in Interest Expense					11
Unrealized gains (losses) reflected in operating revenues related to derivatives still held at the reporting date	188		(170)		245		41
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Unrealized Gain (Loss) Included in Interest Expense related to derivatives still held at reporting date					11
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	384		575		566		486
Realized and unrealized gains (losses): [Abstract]
Included in Earnings	243	[1]	(149)	[1]	253	[2]	135	[2]
Included in regulatory assets and liabilities	2		1		0		7
Purchases	19		40		89		221
Settlements	(3)		30		(59)		(152)
Issuances	(16)		(21)		(110)		(221)
Transfers in	(2)	[3]	5	[3]	(116)	[4]	21	[4]
Transfers out	(3)	[3]	1	[3]	1	[4]	(15)	[4]
Fair value of net derivatives based on significant unobservable inputs, ending balance	624		482		624		482
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	188	[5]	(171)	[5]	256	[6]	41	[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	(1)		7		2		4
Realized and unrealized gains (losses): [Abstract]
Included in Earnings	0		0		0		0
Included in regulatory assets and liabilities	2		1		0		7
Purchases	0		0		0		0
Settlements	0		(3)		(1)		(6)
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	1		5		1		5
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, 2013, realized and unrealized gains of approximately $242 million are reflected in the condensed consolidated statements of income in operating revenues and the balance is reflected in fuel, purchased power and interchange. For the three months ended September 30, 2012, realized and unrealized losses of approximately $149 million are reflected in the condensed consolidated statements of income in operating revenues.

[2] For the nine months ended September 30, 2013, realized and unrealized gains (losses) of approximately $244 million are reflected in the condensed consolidated statements of income in operating revenues, $11 million in interest expense and the balance is reflected in fuel, purchased power and interchange. For the nine months ended September 30, 2012, realized and unrealized gains of approximately $132 million are reflected in the condensed consolidated statements of income in operating revenues and the balance is reflected in fuel, purchased power and interchange.

[3] Transfers into Level 3 were a result of decreased observability of market data. 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] 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.

[5] For the three months ended September 30, 2013, unrealized gains of $188 million are reflected in the condensed consolidated statements of income in operating revenues. For the three months ended September 30, 2012, unrealized losses of approximately $170 million are reflected in the condensed consolidated statements of income in operating revenues and the balance is reflected in fuel, purchased power and interchange.

[6] For the nine months ended September 30, 2013, unrealized gains of approximately $245 million are reflected in the condensed consolidated statements of income in operating revenues and $11 million in interest expense. For the nine months ended September 30, 2012, unrealized gains of approximately $41 million are reflected in the condensed consolidated statements of income in operating revenues.