Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Line of Credit Facility [Line Items]
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.
Maximum [Member]
Line of Credit Facility [Line Items]
Facility size	$ 6,000
Minimum [Member]
Line of Credit Facility [Line Items]
Line of credit facility, expiration date	Nov. 01, 2017
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	6,000	[1]
Available capacity	4,717
Notes payable and commercial paper	(979)	[2]
Outstanding letters of credit	(64)
Tax exempt bonds	(240)
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,250	[1]
Available capacity	871
Notes payable and commercial paper	(300)	[2]
Outstanding letters of credit	(4)
Tax exempt bonds	(75)
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	750	[1]
Available capacity	504
Notes payable and commercial paper	(244)
Outstanding letters of credit	(2)
Duke Energy Florida [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	750	[1]
Available capacity	749
Notes payable and commercial paper	0
Outstanding letters of credit	(1)
Duke Energy Ohio [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	750	[1]
Available capacity	637
Notes payable and commercial paper	(29)
Tax exempt bonds	(84)
Duke Energy Indiana [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	750	[1]
Available capacity	519
Notes payable and commercial paper	(150)	[2]
Tax exempt bonds	(81)
Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,750	[1]
Available capacity	1,437
Notes payable and commercial paper	(256)
Outstanding letters of credit	(57)
Parent Company [Member] | Proceeds Loaned To Subsidiary Registrants [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Notes payable and commercial paper	$ (450)

[1] Represents the sublimit of each borrower at September 30, 2013.

[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.