Regulatory Matters (Schedule of Crystal River Unit 3 Replacements and Repair Costs)(Details) (Crystal River Unit 3 [Member], USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Crystal River Unit 3 [Member]
Replacement Power Costs Incurred	$ 573
Amount Included In Deferred Fuel Regulatory Asset Replacement Power Costs	411	[1]
Amount of repair costs incurred	324
Nuclear Electric Insurance Limited Insurance Recoveries Related To Repair Costs	(143)
Repair Costs To Be Recovered	181	[1]
Nuclear Electric Insurance Limited Insurance Recoveries Related To Replacement Power Costs	$ (162)

[1] See discussion below of Progress Energy Florida's ability to recover prudently incurred fuel and purchased power costs and Crystal River Unit 3 repair costs.