Debt and Credit Facilities (Narrative) (Details) (USD $)	1 Months Ended
Apr. 30, 2015	Mar. 31, 2015
Subsequent Event [Member]
Line of Credit Facility [Line Items]
Repayments of Commercial Paper	$ 1,300,000,000
North Carolina Ash Basins [Member] \| USDOJ [Member] \| Duke Energy Carolinas [Member]
Line of Credit Facility [Line Items]
Minimum Master Credit Facility Balance Required		$ 250,000,000

The cash outflow due to repaying amounts borrowed by issuing commercial paper.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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