Document And Entity Information (USD $)	12 Months Ended
	Dec. 31, 2011	Feb. 21, 2012	Jun. 30, 2011
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2011
Entity Registrant Name	Duke Energy CORP
Entity Central Index Key	0001326160
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Voluntary Filers	No
Entity Public Float			$ 25,020,000,000
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding		1,335,831,211
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	FY
Duke Energy Carolinas [Member]
Entity Registrant Name	Duke Energy Carolinas, LLC
Entity Central Index Key	0000030371
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Duke Energy Ohio [Member]
Entity Registrant Name	Duke Energy Ohio, Inc.
Entity Central Index Key	0000020290
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Duke Energy Indiana [Member]
Entity Registrant Name	Duke Energy Indiana, Inc.
Entity Central Index Key	0000081020
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes