Variable Interest Entities (Consolidated VIEs) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Cash and cash equivalents	$ 2,166		$ 1,424	$ 1,761	$ 2,110
Restricted receivables of VIEs	1,258		1,201
Other current assets	2,191		2,425
Intangibles, net	351		372
Restricted other assets of VIEs	52		62
Investments and other assets	2,361		2,399
Property, plant and equipment, cost	1,679		1,558
Accumulated depreciation and amortization	(33,136)		(31,969)
Other deferred debits	178		178
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	1,819		2,444
Non-recourse notes payable	325		312
Current maturities of long-term debt	2,307		3,110
Other current liabilities	2,330		2,511
Non-recourse long-term debt	1,265		852
Deferred income taxes	11,489		10,490
Asset retirement obligation	5,341		5,169
Other liabilities	1,789		2,221
Noncontrolling interests	72		78
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	527		534
Total assets	527		534
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Non-recourse notes payable	325		312
Total liabilities	325		312
Net assets of consolidated VIEs	202		222
CinCap V [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	17		15
Other current assets	5		4
Restricted other assets of VIEs	40		52
Investments and other assets	12		10
Total assets	74		81
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Current maturities of long-term debt	14		13
Other current liabilities	5		4
Non-recourse long-term debt	37		48
Other liabilities	12		10
Total liabilities	68		75
Net assets of consolidated VIEs	6		6
Renewables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	11		16
Other current assets	199		133
Intangibles, net	11		12
Restricted other assets of VIEs	12		2
Investments and other assets	4
Property, plant and equipment, cost	1,663		1,543
Accumulated depreciation and amortization	(146)		(98)
Other deferred debits	34		40
Total assets	1,788		1,648
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	3		1
Taxes accrued	12		62
Current maturities of long-term debt	62		459
Other current liabilities	26		25
Non-recourse long-term debt	928		504
Deferred income taxes	255		154
Asset retirement obligation	25		23
Other liabilities	102		39
Total liabilities	1,413		1,267
Net assets of consolidated VIEs	375		381
Other VIEs [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs			(1)
Other current assets	2		2
Investments and other assets	3		2
Property, plant and equipment, cost	16		15
Accumulated depreciation and amortization	(5)		(5)
Total assets	16		13
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Net assets of consolidated VIEs	16		13
Total Consolidated VIE [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	1,258		1,201
Other current assets	206		139
Intangibles, net	11		12
Restricted other assets of VIEs	52		54
Investments and other assets	19		12
Property, plant and equipment, cost	1,679		1,558
Accumulated depreciation and amortization	(151)		(103)
Other deferred debits	34		40
Total assets	3,108		2,913
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	3		1
Non-recourse notes payable	325		312
Taxes accrued	12		62
Current maturities of long-term debt	76		472
Other current liabilities	31		29
Non-recourse long-term debt	1,265		852
Deferred income taxes	255		154
Asset retirement obligation	25		23
Other liabilities	114		49
Total liabilities	2,106		1,954
Net assets of consolidated VIEs	1,002		959
Duke Energy Carolinas [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Cash and cash equivalents	25		19	314	289
Restricted receivables of VIEs	703		637
Other current assets	474		439
Investments and other assets	845		934
Accumulated depreciation and amortization	(11,731)		(11,437)
Other deferred debits	45		71
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	451		599
Current maturities of long-term debt	447		406
Other current liabilities	461		490
Non-recourse long-term debt	300		300
Deferred income taxes	5,537		5,181
Asset retirement obligation	2,053		1,959
Other liabilities	732		924
Duke Energy Carolinas [Member] | DERF [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	703	[1]	637
Total assets	703	[1]	637
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Non-recourse long-term debt	300	[1]	300
Total liabilities	300	[1]	300
Net assets of consolidated VIEs	$ 403	[1]	$ 337

[1] Duke Energy Receivables Finance Company, LLC (DERF) is a wholly owned limited liability company of Duke Energy Carolinas.