Fair Value Of Financial Assets and Liabilities (Additional Fair Value Disclosure) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2013		Dec. 31, 2012
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	$ 42,099		$ 44,001
Debt of variable interest entities	1,259		852
Long-term debt	39,582	[1]	39,461	[1]
Duke Energy Carolinas [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	9,461		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	15,462		16,563
Long-term debt	14,220		14,428
Duke Energy Progress [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	5,488		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	5,433		6,222
Long-term debt	4,892		5,320
Duke Energy Ohio [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	1,809		2,117
Long-term debt	1,742		1,997
Duke Energy Indiana [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	4,049		4,268
Long-term debt	$ 3,701		$ 3,702

[1] Includes book value of Non-recourse long-term debt of variable interest entities of $1,259 million and $852 million June 30, 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 June 30, 2013 and December 31, 2012, respectively.