Derivative Instruments (Credit-Risk-Related Contingent Features) (Details) (USD $)	Sep. 30, 2012
Derivative [Line Items]
Fair value of derivative instruments with credit-risk-related contingent features that were in a liability position	$ 2,200,000,000
Total required posted collateral should FPL's and Capital Holdings' credit ratings fall to BBB/Baa2	350,000,000
Total required posted collateral should FLP's and Capital Holdings' credit ratings fall below investment grade	2,200,000,000
Additional collateral requirements if non-ratings based contract provisions are triggered	600,000,000
Letters of credit posted through the normal course of business that could be applied toward the collateral requirements related to derivative instruments with credit-risk-related contingent features	210,000,000
FPL [Member]
Derivative [Line Items]
Fair value of derivative instruments with credit-risk-related contingent features that were in a liability position	115,000,000
Total required posted collateral should FPL's and Capital Holdings' credit ratings fall to BBB/Baa2	10,000,000
Total required posted collateral should FLP's and Capital Holdings' credit ratings fall below investment grade	500,000,000
Additional collateral requirements if non-ratings based contract provisions are triggered	$ 100,000,000