Fair Value Of Financial Assets And Liabilities (Additional Fair Value Disclosure) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013		Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	$ 44,068		$ 44,001
Debt of variable interest entities	1,255		852
Long-term Debt	39,662	[1]	39,461	[1]
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	10,036		10,096
Debt of variable interest entities	300		300
Long-term Debt	8,740	[2]	8,741	[2]
Progress Energy [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	16,276		16,563
Long-term Debt	14,224		14,428
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	5,757		5,277
Long-term Debt	5,336		4,840
Duke Energy Florida [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	5,730		6,222
Long-term Debt	4,894		5,320
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	2,142		2,117
Long-term Debt	1,994		1,997
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	4,228		4,268
Long-term Debt	$ 3,702		$ 3,702

[1] Includes book value of Non-recourse long-term debt of variable interest entities of $1,255 million and $852 million March 31, 2013 and December 31, 2012, respectively.

[2] Includes book value of Non-recourse long-term debt of variable interest entities of $300 million at both March 31, 2013 and December 31, 2012, respectively.