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	6 Months Ended
	Jun. 30, 2012 MWh		Dec. 31, 2011
Megawatt hours of potential plants to be retired	2,773
Remaining net book value of potential plants to be retired	$ 327	[1]
Generation facilities to be retired, net	73		80
Duke Energy Carolinas [Member]
Megawatt hours of potential plants to be retired	1,080	[2],[3]
Remaining net book value of potential plants to be retired	176	[2],[3]
Generation facilities to be retired, net	73		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	138	[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	[5]

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

[2] Includes Riverbend Units 4 through 7, Lee Units 1 through 3 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 June 30, 2012.

[3] Net book value of Buck Units 5 and 6 of $73 million is included in Generation facilities to be retired, net, on the Condensed Consolidated Balance Sheets at June 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.