Variable Interest Entities (Schedule of Non-Consolidated VIEs) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	$ 508		$ 483
Investments and other assets	2,412		2,399
Intangibles	350		372
Other current liabilities	3,026		2,511
Deferred credits and other liabilities	26,525		26,442
Long-term debt	39,582	[1]	39,461	[1]
Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	301		292
Investments and other assets	4		11
Intangibles	100		104
Total assets	405		407
Other current liabilities	3		3
Deferred credits and other liabilities	16		336
Total liabilities	19		339
Net assets (liabilities)	386		68
DukeNet [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	114		118
Total assets	114		118
Net assets (liabilities)	114		118
Renewables [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	158		147
Total assets	158		147
Net assets (liabilities)	158		147
Other VIEs [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Investments in equity method unconsolidated affiliates	29		27
Investments and other assets	4		2
Intangibles	100		104
Total assets	133		133
Other current liabilities	3		3
Deferred credits and other liabilities	16		17
Total liabilities	19		20
Net assets (liabilities)	114		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	948		934
Other current liabilities	441		490
Deferred credits and other liabilities	10,972		10,602
Long-term debt	8,740	[3]	8,741	[3]
Progress Energy [Member]
Variable Interest Entity [Line Items]
Investments and other assets	516		530
Other current liabilities	1,285		1,118
Deferred credits and other liabilities	9,584		9,755
Long-term debt	14,220		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	281		251
Other current liabilities	451		517
Deferred credits and other liabilities	6,626		6,451
Long-term debt	5,336		4,840
Duke Energy Florida [Member]
Variable Interest Entity [Line Items]
Investments and other assets	173		182
Other current liabilities	774		534
Deferred credits and other liabilities	3,836		3,934
Long-term debt	4,892		5,320
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Investments and other assets	80		75
Intangibles	122		129
Other current liabilities	123		126
Deferred credits and other liabilities	2,484		2,473
Long-term debt	1,742		1,997
Duke Energy Ohio [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Receivables	82		97
Intangibles	100		104
Total assets	182		201
Net assets (liabilities)	182		201
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Investments and other assets	124		122
Intangibles	35		41
Other current liabilities	136		165
Deferred credits and other liabilities	2,120		2,005
Long-term debt	3,701		3,702
Duke Energy Indiana [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Receivables	110		116
Total assets	110		116
Net assets (liabilities)	$ 110		$ 116

[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] 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 June 30, 2013 and December 31, 2012, respectively.