Debt And Credit Facilities (Schedule Of Line Of Credit Facilities) (Details) (USD $)	3 Months Ended
	Mar. 31, 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. However, 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.
Master Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	6,000,000,000
Outstanding letters of credit	(60,000,000)
Notes payable and commercial paper	(1,306,000,000)
Tax exempt bonds	(240,000,000)
Available capacity	4,394,000,000
Duke Energy Carolinas [Member] | Master Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	1,250,000,000	[1]
Outstanding letters of credit	(7,000,000)
Notes payable and commercial paper	(300,000,000)	[2]
Tax exempt bonds	(75,000,000)
Available capacity	868,000,000
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Facility Size	750,000,000	[1]
Outstanding letters of credit	(2,000,000)
Notes payable and commercial paper	(26,000,000)
Available capacity	(722,000,000)
Duke Energy Florida [Member]
Line of Credit Facility [Line Items]
Facility Size	750,000,000	[1]
Outstanding letters of credit	(1,000,000)
Notes payable and commercial paper	(162,000,000)
Available capacity	(587,000,000)
Duke Energy Ohio [Member] | Master Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	750,000,000	[1]
Outstanding letters of credit	0
Notes payable and commercial paper	(163,000,000)
Tax exempt bonds	(84,000,000)
Available capacity	503,000,000
Duke Energy Ohio [Member] | Duke Energy Kentucky [Member] | Master Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	100,000,000
Duke Energy Indiana [Member] | Master Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	750,000,000	[1]
Outstanding letters of credit	0
Notes payable and commercial paper	(169,000,000)	[2]
Tax exempt bonds	(81,000,000)
Available capacity	500,000,000
Parent Company [Member] | Master Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	1,750,000,000	[1]
Outstanding letters of credit	(50,000,000)
Notes payable and commercial paper	(486,000,000)	[2]
Available capacity	1,214,000,000
Parent Company [Member] | Proceeds Loaned To Subsidiary Registrants [Member]
Line of Credit Facility [Line Items]
Notes payable and commercial paper	$ 450,000,000

[1] Represents the sublimit of each borrower at March 31, 2013. The Duke Energy Ohio sublimit includes $100 million for Duke Energy Kentucky.

[2] Duke Energy issued $450 million of commercial paper and loaned the proceeds through the money pool to Duke Energy Carolinas and Duke Energy Indiana. The balances are classified as long-term borrowings within Long-term Debt in Duke Energy Carolina’s and Duke Energy Indiana’s Condensed Consolidated Balance Sheets.