Income Taxes And Other Taxes (Schedule Of Effective Tax Rates) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Effective tax rate	32.20%	30.40%	29.80%	30.80%
Duke Energy Carolinas [Member]
Effective tax rate	37.20%	35.50%	36.70%	35.30%
Duke Energy Ohio [Member]
Effective tax rate	39.90%	9.60%	38.10%	30.40%
Duke Energy Indiana [Member]
Effective tax rate	34.40%	29.30%	45.70%	32.30%