Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012
Line of Credit Facility [Line Items]
Line of credit facility, expiration date	Dec. 01, 2018
Notes payable and commercial paper	$ (1,289)	[1]	$ (1,507)	[2]
Tax exempt bonds	(2,356)	[3]	(2,357)	[3]
Maximum [Member]
Line of Credit Facility [Line Items]
Facility size	6,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	6,000	[4]
Available capacity	5,248
Notes payable and commercial paper	(450)	[5]
Outstanding letters of credit	(62)
Tax exempt bonds	(240)
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(395)	[3]	(395)	[3]
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,000	[4]
Available capacity	621
Notes payable and commercial paper	(300)	[5]
Outstanding letters of credit	(4)
Tax exempt bonds	(75)
Progress Energy [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(910)	[3]	(910)	[3]
Duke Energy Progress [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(669)	[3]	(669)	[3]
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	750	[4]
Available capacity	748
Outstanding letters of credit	(2)
Duke Energy Florida [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(241)	[3]	(241)	[3]
Duke Energy Florida [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	650	[4]
Available capacity	649
Outstanding letters of credit	(1)
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(479)	[3]	(479)	[3]
Duke Energy Ohio [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	650	[4]
Available capacity	566
Tax exempt bonds	(84)
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Tax exempt bonds	(573)	[3]	(573)	[3]
Duke Energy Indiana [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	700	[4]
Available capacity	469
Notes payable and commercial paper	(150)	[5]
Tax exempt bonds	(81)
Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	2,250	[4]
Available capacity	2,195
Outstanding letters of credit	$ (55)

[1] Includes $450 million that was classified as Long-term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that back-stop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted-average days to maturity was 49 days.

[2] Includes $450 million that was classified as Long-term Debt on the Consolidated Balance Sheets due to the existence of long-term credit facilities that back-stop these commercial paper balances, along with Duke Energy’s ability and intent to refinance these balances on a long-term basis. The weighted-average days to maturity was 18 days.

[3] Substantially all tax-exempt bonds are secured by first mortgage bonds or letters of credit.

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

[5] 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 Carolinas' and Duke Energy Indiana's Condensed Consolidated Balance Sheets.