v2.4.0.6

Fair Value Of Financial Assets And Liabilities (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Auction Rate Securities [Abstract]
Settlements	$ 7	$ (9)
Interest Rate Current [Member]
Auction Rate Securities [Abstract]
Level 3 ARS Assumptions	0.30%
Auction Rate Securities [Member] | Discounted Cash Flow [Member] | Risk Adjusted Discount Rates [Member]
Auction Rate Securities [Abstract]
Level 3 ARS Assumptions	5.00%
Duke Energy Carolinas [Member]
Auction Rate Securities [Abstract]
Settlements	7
Duke Energy Ohio [Member]
Auction Rate Securities [Abstract]
Settlements	(3)
Duke Energy Indiana [Member]
Auction Rate Securities [Abstract]
Settlements		$ (10)

X

- Details

Name:	duk_AuctionRateSecuritiesAbstract
Namespace Prefix:	duk_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Assumptions used in valuing Level 3 ARS investments

+ References

No definition available.

+ Details

Name:	duk_Level3ArsAssumptions
Namespace Prefix:	duk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Settlements that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration