Variable Interest Entities (Consolidated VIEs) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013		Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Cash and cash equivalents	$ 1,571		$ 1,424	$ 1,526	$ 2,110
Restricted receivables of VIEs	1,235		1,201
Other current assets	2,066		2,425
Intangibles, net	350		372
Restricted other assets of VIEs	57		62
Investments and other assets	2,412		2,399
Property, plant and equipment, cost	1,666		1,558
Accumulated depreciation and amortization	(32,511)		(31,969)
Other deferred debits	177		178
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	1,936		2,444
Non-recourse notes payable	325		312
Current maturities of long-term debt	2,223		3,110
Other current liabilities	3,026		2,511
Non-recourse long-term debt	1,259		852
Deferred income taxes	10,829		10,490
Asset retirement obligation	5,284		5,169
Other liabilities	2,106		2,221
Noncontrolling interests	69		78
Cinergy Receivables [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	528		534
Total assets	528		534
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Non-recourse notes payable	325		312
Total liabilities	325		312
Net assets of consolidated VIEs	203		222
CinCap V [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	16		15
Other current assets	4		4
Restricted other assets of VIEs	44		52
Investments and other assets	11		10
Total assets	75		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	41		48
Other liabilities	9		10
Total liabilities	69		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	20		16
Other current assets	183		133
Intangibles, net	11		12
Restricted other assets of VIEs	12		2
Investments and other assets	1
Property, plant and equipment, cost	1,650		1,543
Accumulated depreciation and amortization	(137)		(98)
Other deferred debits	33		40
Total assets	1,773		1,648
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	3		1
Taxes accrued	4		62
Current maturities of long-term debt	61		459
Other current liabilities	19		25
Non-recourse long-term debt	918		504
Deferred income taxes	271		154
Asset retirement obligation	24		23
Other liabilities	21		39
Total liabilities	1,321		1,267
Net assets of consolidated VIEs	452		381
Other VIEs [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Restricted receivables of VIEs	2		(1)
Other current assets	2		2
Restricted other assets of VIEs	1
Investments and other assets			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]
Total liabilities			0
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	1,235		1,201
Other current assets	189		139
Intangibles, net	11		12
Restricted other assets of VIEs	57		54
Investments and other assets	12		12
Property, plant and equipment, cost	1,666		1,558
Accumulated depreciation and amortization	(142)		(103)
Other deferred debits	33		40
Total assets	3,061		2,913
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	3		1
Non-recourse notes payable	325		312
Taxes accrued	4		62
Current maturities of long-term debt	75		472
Other current liabilities	24		29
Non-recourse long-term debt	1,259		852
Deferred income taxes	271		154
Asset retirement obligation	24		23
Other liabilities	30		49
Total liabilities	2,015		1,954
Noncontrolling interests	0
Net assets of consolidated VIEs	1,046		959
Duke Energy Carolinas [Member]
Variable Interest Entity Consolidated Carrying Amount Assets [Abstract]
Cash and cash equivalents	13		19	18	289
Restricted receivables of VIEs	669		637
Other current assets	457		439
Investments and other assets	948		934
Accumulated depreciation and amortization	(11,502)		(11,437)
Other deferred debits	47		71
Variable Interest Entity Consolidated Carrying Amount Liabilities [Abstract]
Accounts payable	487		599
Current maturities of long-term debt	406		406
Other current liabilities	441		490
Non-recourse long-term debt	300		300
Deferred income taxes	5,421		5,181
Asset retirement obligation	2,021		1,959
Other liabilities	882		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	669	[1]	637
Total assets	669	[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	$ 369	[1]	$ 337

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