Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) (USD $)	6 Months Ended
	Jun. 30, 2013
Line of Credit Facility [Line Items]
Line of credit facility, expiration date	Nov. 01, 2016
Extended facility size	$ 5,630,000,000
Line of credit facility, extended expiration date	Nov. 01, 2017
Line of credit facility, affiliated borrower	The Duke Energy Registrants each have borrowing capacity under the master credit facility up to specified sublimits for each borrower. Duke Energy has the unilateral ability at any time to increase or decrease the borrowing sublimits of each borrower, subject to a maximum sublimit for each borrower.
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	6,000,000,000
Reduction to Backstop Issuances [Abstract]
Notes payable and commercial paper	(1,330,000,000)
Outstanding letters of credit	(68,000,000)
Tax exempt bonds	(240,000,000)
Available capacity	4,362,000,000
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,250,000,000
Reduction to Backstop Issuances [Abstract]
Notes payable and commercial paper	(300,000,000)
Outstanding letters of credit	(7,000,000)
Tax exempt bonds	(75,000,000)
Available capacity	868,000,000
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	750,000,000
Reduction to Backstop Issuances [Abstract]
Notes payable and commercial paper	(197,000,000)
Outstanding letters of credit	(2,000,000)
Available capacity	551,000,000
Duke Energy Florida [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	750,000,000
Reduction to Backstop Issuances [Abstract]
Notes payable and commercial paper	(8,000,000)
Outstanding letters of credit	(1,000,000)
Available capacity	741,000,000
Duke Energy Ohio [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	750,000,000
Reduction to Backstop Issuances [Abstract]
Notes payable and commercial paper	(445,000,000)
Tax exempt bonds	(84,000,000)
Available capacity	221,000,000
Duke Energy Ohio [Member] | Duke Energy Kentucky [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	100,000,000
Duke Energy Indiana [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	750,000,000
Reduction to Backstop Issuances [Abstract]
Notes payable and commercial paper	(150,000,000)
Tax exempt bonds	(81,000,000)
Available capacity	519,000,000
Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,750,000,000
Reduction to Backstop Issuances [Abstract]
Notes payable and commercial paper	(230,000,000)
Outstanding letters of credit	(58,000,000)
Available capacity	1,462,000,000
Parent Company [Member] | Proceeds Loaned To Subsidiary Registrants [Member] | Revolving Credit Facility [Member]
Reduction to Backstop Issuances [Abstract]
Notes payable and commercial paper	$ 450,000,000