Regulatory Matters (Schedule Of Net Carrying Value Of Facilities As Well As The Remaining Non-current Regulatory Assets) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012 MWh		Dec. 31, 2011
Megawatt hours of potential plants to be retired	4,642
Remaining net book value of potential plants to be retired	$ 583	[1]
Generation facilities to be retired, net	232		80
Duke Energy Carolinas [Member]
Megawatt hours of potential plants to be retired	910	[2],[3]
Remaining net book value of potential plants to be retired	117	[1],[2],[3]
Generation facilities to be retired, net	68		80
Retired MW	587
Committed to retire	1,667
Duke Energy Indiana [Member]
Megawatt hours of potential plants to be retired	668	[4]
Remaining net book value of potential plants to be retired	134	[1],[4]
Duke Energy Ohio [Member]
Megawatt hours of potential plants to be retired	1,025	[5]
Remaining net book value of potential plants to be retired	13	[1],[5]
Progress Energy Carolinas [Member]
Megawatt hours of potential plants to be retired	1,166	[3],[6]
Remaining net book value of potential plants to be retired	164	[1],[3],[6]
Progress Energy Florida [Member]
Megawatt hours of potential plants to be retired	873	[7]
Remaining net book value of potential plants to be retired	$ 155	[1],[7]

[1] Included in Property, plant and equipment, net as of September 30, 2012, on the Condensed Consolidated Balance Sheets, unless otherwise noted.

[2] Includes Riverbend Units 4 through 7, Lee Units 1 and 2 and Buck Units 5 and 6. Duke Energy Carolinas has committed to retire 1,667 MW in conjunction with a Cliffside air permit settlement, of which 587 MW have already been retired as of September 30, 2012. Excludes 170 MW Lee Unit 3 that is expected to be converted to gas in 2014. The Lee Unit 3 conversion will be considered a retirement towards meeting the 1,667 MW retirement commitment.

[3] Net book value of Duke Energy Carolinas' Buck Units 5 and 6 of $68 million, and Progress Energy Carolinas' Cape Fear, Robinson, Sutton and six combustion turbine units of $164 million is included in Generation facilities to be retired, net, on the Condensed Consolidated Balance Sheets at September 30, 2012.

[4] Includes Wabash River Units 2 through 6.

[5] Includes Beckjord Station and Miami Fort Unit 6. Beckjord has no remaining book value.

[6] Includes Cape Fear, Robinson and six combustion turbine units, which were retired on October 1, 2012, and Sutton, which is expected to be retired by the end of 2013.

[7] Includes Crystal River Units 1 and 2.