Debt And Credit Facilities (Schedule Of Line Of Credit Facilities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Line of Credit Facility [Line Items]
Notes Payable and Commercial Paper	$ (1,195)	[1]	$ (604)	[2]
Tax Exempt Bonds	(2,357)	[3]	(1,515)	[4]
Debt to total capitalization percentage, for each borrower	65
Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Tax Exempt Bonds	(395)	[3]	(415)	[4]
Debt to total capitalization percentage, for each borrower	65
Progress Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Facility Size	750
Outstanding Letters of Credit	(2)
Notes Payable and Commercial Paper			(188)
Tax Exempt Bonds	(669)	[3]	(669)	[4]
Available Capacity	(748)
Progress Energy Florida [Member]
Line of Credit Facility [Line Items]
Facility Size	750
Outstanding Letters of Credit	(1)
Tax Exempt Bonds	(241)	[3]	(241)	[4]
Available Capacity	(749)
Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Tax Exempt Bonds	(479)	[3]	(525)	[4]
Debt to total capitalization percentage, for each borrower	65
Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Tax Exempt Bonds	(573)	[3]	(574)	[4]
Debt to total capitalization percentage, for each borrower	65
Master Credit Facility [Member]
Line of Credit Facility [Line Items]
Facility Size	6,000
Outstanding Letters of Credit	(60)
Notes Payable and Commercial Paper	(800)
Tax Exempt Bonds	(240)
Available Capacity	4,900
Master Credit Facility [Member] | Duke Energy Corp [Member]
Line of Credit Facility [Line Items]
Facility Size	1,750
Outstanding Letters of Credit	(50)
Notes Payable and Commercial Paper	(195)
Tax Exempt Bonds	0
Available Capacity	1,505
Master Credit Facility [Member] | Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Facility Size	1,250
Outstanding Letters of Credit	(7)
Notes Payable and Commercial Paper	(300)
Tax Exempt Bonds	(75)
Available Capacity	868
Master Credit Facility [Member] | Duke Energy Ohio [Member]
Line of Credit Facility [Line Items]
Facility Size	750
Outstanding Letters of Credit	0
Notes Payable and Commercial Paper	(104)
Tax Exempt Bonds	(84)
Available Capacity	562
Master Credit Facility [Member] | Duke Energy Indiana [Member]
Line of Credit Facility [Line Items]
Facility Size	750
Outstanding Letters of Credit	0
Notes Payable and Commercial Paper	(201)
Tax Exempt Bonds	(81)
Available Capacity	$ 468

[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 18 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 17 days.

[3] $1.558 billion, $360 million, $910 million, $669 million, $241 million and $288 million were secured by first mortgage bonds at Duke Energy, Duke Energy Carolinas, Progress Energy, Progress Energy Carolinas, Progress Energy Florida and Duke Energy Indiana, respectively, and $231 million, $27 million and $204 million were secured by a letter of credit at Duke Energy, Duke Energy Ohio, and Duke Energy Indiana, respectively.

[4] $650 million, $360 million, $910 million, $669 million, $241 million and $289 million were secured by first mortgage bonds at Duke Energy, Duke Energy Carolinas, Progress Energy, Progress Energy Carolinas, Progress Energy Florida and Duke Energy Indiana, respectively, and $231 million, $27 million and $204 million were secured by a letter of credit at Duke Energy, Duke Energy Ohio, and Duke Energy Indiana, respectively.