Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 511		$ 483
Investments and other assets	2,361		2,399
Intangibles	351		372
Other current liabilities	2,330		2,511
Deferred credits and other liabilities	26,712		26,442
Long-term debt	39,709	[1]	39,461	[1]
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	290		292
Investments and other assets	4		11
Intangibles	100		104
Total assets	394		407
Other current liabilities	2		3
Deferred credits and other liabilities	15		336
Total liabilities	17		339
Net assets (liabilities)	377		68
DukeNet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	113		118
Total assets	113		118
Net assets (liabilities)	113		118
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	152		147
Total assets	152		147
Net assets (liabilities)	152		147
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	25		27
Investments and other assets	4		2
Intangibles	100		104
Total assets	129		133
Other current liabilities	2		3
Deferred credits and other liabilities	15		17
Total liabilities	17		20
Net assets (liabilities)	112		113
FPC Capital I Trust [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments and other assets			9	[2]
Total assets			9
Deferred credits and other liabilities			319	[2]
Total liabilities			319
Net assets (liabilities)			(310)
Duke Energy Carolinas [Member]
Variable Interest Entity [Line Items]
Investments and other assets	845		934
Other current liabilities	461		490
Deferred credits and other liabilities	11,228		10,602
Long-term debt	8,739	[3]	8,741	[3]
Progress Energy [Member]
Variable Interest Entity [Line Items]
Investments and other assets	531		530
Other current liabilities	1,177		1,118
Deferred credits and other liabilities	9,313		9,755
Long-term debt	13,815		14,428
Progress Energy [Member] | FPC Capital I Trust [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments and other assets			9
Deferred credits and other liabilities			274
Duke Energy Progress [Member]
Variable Interest Entity [Line Items]
Investments and other assets	297		251
Other current liabilities	440		517
Deferred credits and other liabilities	6,463		6,451
Long-term debt	4,936		4,840
Duke Energy Florida [Member]
Variable Interest Entity [Line Items]
Investments and other assets	176		182
Other current liabilities	667		534
Deferred credits and other liabilities	3,843		3,934
Long-term debt	4,887		5,320
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Investments and other assets	98		75
Intangibles	120		129
Other current liabilities	114		126
Deferred credits and other liabilities	2,545		2,473
Long-term debt	2,188		1,997
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Receivables	75		97
Intangibles	98		104
Total assets	173		201
Net assets (liabilities)	173		201
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Investments and other assets	160		122
Intangibles	33		41
Other current liabilities	101		165
Deferred credits and other liabilities	2,294		2,005
Long-term debt	3,798		3,702
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Receivables	114		116
Total assets	114		116
Net assets (liabilities)	$ 114		$ 116

[1] Includes book value of Non-recourse long-term debt of variable interest entities of $1,265 million and $852 million September 30, 2013 and December 31, 2012, respectively.

[2] The entire balance of Investments and other assets and $274 million of the Deferred credits and other liabilities balance applies to Progress Energy.

[3] Includes book value of Non-recourse long-term debt of variable interest entities of $300 million at both September 30, 2013 and December 31, 2012, respectively.