Debt and Credit Facilities (Schedule of Line of Credit Facilities) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014
Line of Credit Facility [Line Items]
Facility size	$ 6,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	6,000	[1]
Notes payable and commercial paper	(1,409)	[2]
Outstanding letters of credit	(64)
Tax exempt bonds	(156)
Available capacity	4,371
Parent Company [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	2,250	[1]
Notes payable and commercial paper	(873)	[2]
Outstanding letters of credit	(57)
Tax exempt bonds	0
Available capacity	1,320
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)
Duke Energy Carolinas [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	1,000	[1]
Notes payable and commercial paper	(300)	[2]
Outstanding letters of credit	(4)
Tax exempt bonds	(75)
Available capacity	621
Duke Energy Progress [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	750	[1]
Notes payable and commercial paper	(75)
Outstanding letters of credit	(2)
Tax exempt bonds	0
Available capacity	673
Duke Energy Florida [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	650	[1]
Notes payable and commercial paper	0
Outstanding letters of credit	(1)
Tax exempt bonds	0
Available capacity	649
Duke Energy Ohio [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	650	[1]
Notes payable and commercial paper	(11)
Outstanding letters of credit	0
Tax exempt bonds	0
Available capacity	639
Duke Energy Indiana [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility size	700	[1]
Notes payable and commercial paper	(150)	[2]
Outstanding letters of credit	0
Tax exempt bonds	(81)
Available capacity	$ 469

[1] Represents the sublimit of each borrower at June 30, 2014.

[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 within Long-term Debt in Duke Energy Carolinas' and Duke Energy Indiana’s Condensed Consolidated Balance Sheets.