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, 2012		Dec. 31, 2011
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	$ 1,421		$ 1,241
Tax Exempt Bonds [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	471	[1]	491	[2]
Notes Payable And Commercial Paper [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	450	[3]	450	[4]
Revolving Loan [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	200	[5]
Derf [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	300	[6]	300
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	675		695
Duke Energy Carolinas [Member] | Tax Exempt Bonds [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	75	[7]	95	[8]
Duke Energy Carolinas [Member] | Notes Payable And Commercial Paper [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	300		300	[4]
Duke Energy Carolinas [Member] | Derf [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	300		300
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	111		111
Duke Energy Ohio [Member] | Tax Exempt Bonds [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	111	[9]	111	[10]
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	435		435
Duke Energy Indiana [Member] | Tax Exempt Bonds [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	285	[11]	285	[12]
Duke Energy Indiana [Member] | Notes Payable And Commercial Paper [Member]
Line of Credit Facility [Line Items]
Short-term borrowings classified as long-term debt	$ 150		$ 150	[4]

[1] Of the $471 million of tax-exempt bonds outstanding at December 31, 2012 at Duke Energy, the master credit facility served as a backstop for $240 million of these tax-exempt bonds, with the remaining balance backstopped by other specific long-term credit facilities separate from the master credit facility.

[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] 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 and Duke Energy Indiana as of December 31, 2012.

[4] 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.

[5] Duke Energy International Energy's revolving loan is due in December 2013 with the right to extend the maturity date for additional one year periods with a final maturity date no later than December 2026.

[6] Duke Energy Receivables Finance Company, LLC (DERF) is a wholly owned limited liability company of Duke Energy Carolinas. See Note 18 for further information.

[7] For Duke Energy Carolinas, the master credit facility served as a backstop for the $75 million of tax-exempt bonds outstanding at December 31, 2012.

[8] 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.

[9] Of the $111 million of tax-exempt bonds outstanding at December 31, 2012 at Duke Energy Ohio, the master credit facility served as a backstop for $84 million of these tax-exempt bonds, with the remaining balance backstopped by other specific long-term credit facilities separate from the master credit facility.

[10] For Duke Energy Ohio, this master credit facility (of which $27 million is in the form of letters of credit) served as a backstop for the $111 million of tax-exempt bonds outstanding at December 31, 2011.

[11] Of the $285 million of tax-exempt bonds outstanding at December 31, 2012 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.

[12] 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.