Debt And Credit Facilities (Schedule Of Line Of Credit Facilities) (Details) (Master Credit Facility [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2012
Facility Size	$ 6,000
Outstanding Letters of Credit	(61)
Notes Payable and Commercial Paper	(762)
Tax Exempt Bonds	(260)
Available Capacity	4,917
Duke Energy Corp [Member]
Facility Size	1,750
Outstanding Letters of Credit	(51)
Notes Payable and Commercial Paper	(57)
Tax Exempt Bonds	0
Available Capacity	1,642
Duke Energy Carolinas [Member]
Facility Size	1,250
Outstanding Letters of Credit	(7)
Notes Payable and Commercial Paper	(300)
Tax Exempt Bonds	(95)
Available Capacity	848
Progress Energy Carolinas [Member]
Facility Size	750
Outstanding Letters of Credit	(2)
Notes Payable and Commercial Paper	(134)
Tax Exempt Bonds	0
Available Capacity	614
Progress Energy Florida [Member]
Facility Size	750
Outstanding Letters of Credit	(1)
Notes Payable and Commercial Paper	(121)
Tax Exempt Bonds	0
Available Capacity	628
Duke Energy Ohio [Member]
Facility Size	750
Outstanding Letters of Credit	0
Notes Payable and Commercial Paper	0
Tax Exempt Bonds	(84)
Available Capacity	666
Duke Energy Indiana [Member]
Facility Size	750
Outstanding Letters of Credit	0
Notes Payable and Commercial Paper	(150)
Tax Exempt Bonds	(81)
Available Capacity	$ 519