Income Taxes And Other Taxes (Schedule Of Unrecognized Tax Benefits) (Details) (USD $) In Millions	Sep. 30, 2011		Dec. 31, 2010
Income Taxes And Other Taxes
Unrecognized tax benefits	$ 392	[1]	$ 342	[1]
Amount that if recognized, would affect the effective tax rate or regulatory liability	121	[2]
Amount that if recognized, would be recorded as a component of discontinued operations	$ 11

[1] The Duke Registrants do not anticipate a significant increase or decrease in unrecognized tax benefits in the next twelve months.

[2] Duke Energy and Duke Energy Carolinas are unable to estimate the specific amounts that would affect the effective tax rate or regulatory liability.