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	12 Months Ended
	Dec. 31, 2011 mW
Coal-Fired Generation Capacity, in Megawatts	3,329
Remaining net book value	$ 353	[1]
Remaining non-current regulatory asset	73	[2]
Duke Energy Carolinas [Member]
Coal-Fired Generation Capacity, in Megawatts	1,356	[3]
Remaining net book value	199	[1],[3]
Duke Energy Indiana [Member]
Coal-Fired Generation Capacity, in Megawatts	1,025	[4],[5]
Remaining net book value	14	[1],[4],[5]
Duke Energy Ohio [Member]
Coal-Fired Generation Capacity, in Megawatts	948	[6]
Remaining net book value	140	[1],[6]
Remaining non-current regulatory asset	$ 73	[2],[6]

[1] Included in Property, plant and equipment, net as of December 31, 2011, on the Consolidated Balance Sheets.

[2] On February 1, 2012, 280 MW for Gallagher units 1 and 3 were retired by Duke Energy Indiana. In its December 28, 2011 order, the IURC allowed recovery of and return on the carrying value of the Gallagher units over the original life of these units and classification of this amount as a regulatory asset.

[3] Includes Dan River, Riverbend, Lee 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 311 MW have already been retired as of December 31, 2011. See Note 5 for additional information related to the Cliffside air permit.

[4] Includes Beckjord and Miami Fort unit 6.

[5] Beckjord has no remaining net book value - See Note 12 for additional information.

[6] Includes Wabash River units 2-6 and Gallagher units 1 and 3.