Regulatory Matters (Schedule of Crystal River Unit 3 Replacements and Repair Costs)(Details) (Crystal River Unit 3 [Member], Progress Energy Florida [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Crystal River Unit 3 [Member] | Progress Energy Florida [Member]
Replacement Power Costs Incurred	$ 614
Amount Included In Deferred Fuel Regulatory Asset Replacement Power Costs	452	[1]
Amount of repair costs incurred	338
Total replacement and repair costs incurred	952
Nuclear Electric Insurance Limited Insurance Total Recoveries	(305)
Total balance for recovery of Crystal River Unit 3 Costs	647
Nuclear Electric Insurance Limited Insurance Recoveries Related To Repair Costs	(143)
Repair Costs To Be Recovered	195	[1]
Nuclear Electric Insurance Limited Insurance Recoveries Related To Replacement Power Costs	$ (162)

[1] The portion of replacement power costs that has not been previously recovered from retail customers is classified within Regulatory assets on Duke Energy's Consolidated Balance Sheets and Progress Energy Florida's Balance Sheet as of December 31, 2012. Also, the $195 million of repair costs are classified within Regulatory assets on Duke Energy's Consolidated Balance Sheets and Progress Energy Florida's Balance Sheets as of December 31, 2012.