Debt And Credit Facilities (Schedule Of Tax Exempt Bonds, Commercial Paper Issuances And Money Pool Borrowings) (Details (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Debt And Credit Facilities [Abstract]
Tax Exempt Bonds	$ 491	[1],[2],[3],[4]	$ 632	[1],[5],[6],[7]
Notes Payable and commercial paper	450	[8]
Commercial Paper	450	[8]
DERF	300	[9]	300	[9]
Total	$ 1,241		$ 1,382

[1] For Duke Energy Carolinas, the master credit facility served as a backstop for the $95 million of tax-exempt bonds outstanding at December 31, 2011.

[2] Of the $491 million of tax-exempt bonds outstanding at December 31, 2011 at Duke Energy, the master credit facility served as a backstop for $287 million of these tax-exempt bonds (of which $27 million is in the form of letters of credit), with the remaining balance backstopped by other specific long-term credit facilities separate from the master credit facility.

[3] All of the $111 million of tax-exempt bonds outstanding at December 31, 2011 at Duke Energy Ohio were backstopped by Duke Energy's master credit facility (of which $27 million is in the form of letters of credit).

[4] Of the $285 million of tax-exempt bonds outstanding at December 31, 2011 at Duke Energy Indiana, $81 million were backstopped by Duke Energy's master credit facility, with the remaining balance backstopped by other specific long-term credit facilities separate from the master credit facility.

[5] Of the $632 million of tax-exempt bonds outstanding at December 31, 2010, at Duke Energy, the master credit facility served as a backstop for $311 million of these tax-exempt bonds (of which $27 million is in the form of letters of credit), with the remaining balance backstopped by other specific long-term credit facilities separate from the master credit facility.

[6] Of the $161 million of tax-exempt bonds outstanding at December 31, 2010 at Duke Energy Ohio, $111 million were backstopped by Duke Energy's master credit facility (of which $27 million is in the form of letters of credit), with the remaining balance backstopped by other specific long-term credit facilities separate from the master credit facility.

[7] Of the $352 million of tax-exempt bonds outstanding at December 31, 2010 at Duke Energy Indiana, $81 million were backstopped by Duke Energy's master credit facility, with the remaining balance backstopped by other specific long-term credit facilities separate from the master credit facility.

[8] Duke Energy has issued $450 million in Commercial Paper, which is backstopped by the master credit facility, and the proceeds are in the form of loans through the money pool to Duke Energy Carolinas of $300 million and Duke Energy Indiana of $150 million as of December 31, 2011.

[9] DERF is a short-term obligation backed by a credit facility which expires in August 2013.