Fair Value Measurements (Assets and Liabilities Measured on a Recurring Basis) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Derivatives [Abstract]
Fair value of investments in commingled funds whose underlying investments would be Level 1 if those investments were held directly by the registrant	$ 1,086		$ 1,084
Fair Value, Measurements, Recurring [Member]
Assets [Abstract]
Cash equivalents - equity securities	159		122
Special use funds [Abstract]
Equity securities	1,915		1,986
U.S. Government and municipal bonds	675		622
Corporate debt securities	516		486
Mortgage-backed securities	511		447
Other debt securities	47		108
Other investments [Abstract]
Equity securities	4		4
U.S. Government and municipal bonds	8		12
Corporate debt securities	43		32
Mortgage-backed securities	33		58
Other	10		15
Derivatives [Abstract]
Commodity contracts	1,520	[1]	940	[1]
Interest rate swaps	37	[1]	107	[1]
Foreign currency swaps	27	[1]	48	[1]
Derivatives [Abstract]
Commodity contracts	1,302	[1]	652	[1]
Interest rate swaps	320	[1]	123	[1]
Foreign currency swaps	9	[1]	4	[1]
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair Value, Measurements, Recurring [Member]
Assets [Abstract]
Cash equivalents - equity securities	159		0
Special use funds [Abstract]
Equity securities	709		741
U.S. Government and municipal bonds	508		495
Corporate debt securities	0		0
Mortgage-backed securities	0		0
Other debt securities	0		0
Other investments [Abstract]
Equity securities	4		3
U.S. Government and municipal bonds	8		8
Corporate debt securities	0		0
Mortgage-backed securities	0		0
Other	5		5
Derivatives [Abstract]
Commodity contracts	2,448		1,755
Interest rate swaps	0		0
Foreign currency swaps	0		0
Derivatives [Abstract]
Commodity contracts	2,588		1,821
Interest rate swaps	0		0
Foreign currency swaps	0		0
Significant Other Observable Inputs (Level 2) [Member] | Fair Value, Measurements, Recurring [Member]
Assets [Abstract]
Cash equivalents - equity securities	0		122
Special use funds [Abstract]
Equity securities	1,206	[2]	1,245	[3]
U.S. Government and municipal bonds	167		127
Corporate debt securities	516		486
Mortgage-backed securities	511		447
Other debt securities	47		108
Other investments [Abstract]
Equity securities	0		1
U.S. Government and municipal bonds	0		4
Corporate debt securities	43		32
Mortgage-backed securities	33		58
Other	5		10
Derivatives [Abstract]
Commodity contracts	3,478		1,538
Interest rate swaps	37		107
Foreign currency swaps	27		48
Derivatives [Abstract]
Commodity contracts	3,582		1,509
Interest rate swaps	320		123
Foreign currency swaps	9		4
Significant Unobservable Inputs (Level 3) [Member] | Fair Value, Measurements, Recurring [Member]
Assets [Abstract]
Cash equivalents - equity securities	0		0
Special use funds [Abstract]
Equity securities	0		0
U.S. Government and municipal bonds	0		0
Corporate debt securities	0		0
Mortgage-backed securities	0		0
Other debt securities	0		0
Other investments [Abstract]
Equity securities	0		0
U.S. Government and municipal bonds	0		0
Corporate debt securities	0		0
Mortgage-backed securities	0		0
Other	0		0
Derivatives [Abstract]
Commodity contracts	1,071		824
Interest rate swaps	0		0
Foreign currency swaps	0		0
Derivatives [Abstract]
Commodity contracts	585		528
Interest rate swaps	0		0
Foreign currency swaps	0		0
Netting and Collateral [Member] | Fair Value, Measurements, Recurring [Member]
Assets [Abstract]
Cash equivalents - equity securities	0	[4]	0	[4]
Special use funds [Abstract]
Equity securities	0	[4]	0	[4]
U.S. Government and municipal bonds	0	[4]	0	[4]
Corporate debt securities	0	[4]	0	[4]
Mortgage-backed securities	0	[4]	0	[4]
Other debt securities	0	[4]	0	[4]
Other investments [Abstract]
Equity securities	0	[4]	0	[4]
U.S. Government and municipal bonds	0	[4]	0	[4]
Corporate debt securities	0	[4]	0	[4]
Mortgage-backed securities	0	[4]	0	[4]
Other	0	[4]	0	[4]
Derivatives [Abstract]
Commodity contracts	(5,477)	[4]	(3,177)	[4]
Interest rate swaps	0	[4]	0	[4]
Foreign currency swaps	0	[4]	0	[4]
Derivatives [Abstract]
Commodity contracts	(5,453)	[4]	(3,206)	[4]
Interest rate swaps	0	[4]	0	[4]
Foreign currency swaps	$ 0	[4]	$ 0	[4]

[1] See Note 3 for a reconciliation of net derivatives to NEE's and FPL's consolidated balance sheets.

[2] At NEE, approximately $1,086 million ($979 million at FPL) are invested in commingled funds whose underlying investments would be Level 1 if those investments were held directly by NEE or FPL.

[3] At NEE, approximately $1,084 million ($980 million at FPL) are invested in commingled funds whose underlying investments would be Level 1 if those investments were held directly by NEE or FPL.

[4] Includes the effect of the contractual ability to settle contracts under master netting arrangements and margin cash collateral payments and receipts.