Debt and Credit Facilities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Investment balance	$ 64
Investment balance, debt obligations	64
Proceeds from sales of notes	395	79
Line of Credit Facility, Expiration Date	Aug. 01, 2014
Non-Recourse Long-Term Debt	852	949
Other loans outstanding against cash surrender value of life insurance policies	496	457
Debt to total capitalization percentage, for each borrower	65
Current maturities of long-term debt	3,110	1,894
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Non-Recourse Long-Term Debt	300	300
Debt to total capitalization percentage, for each borrower	65
Current maturities of long-term debt	406	1,178
Progress Energy [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	843	961
Progress Energy Carolinas [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	750
Available Capacity	(748)
Current maturities of long-term debt	407	502
Progress Energy Florida [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	750
Available Capacity	(749)
Current maturities of long-term debt	435	10
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Debt to total capitalization percentage, for each borrower	65
Current maturities of long-term debt	261	507
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Debt to total capitalization percentage, for each borrower	65
Current maturities of long-term debt	405	6
First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 372