Ownership of Coal-fired Facilities (Narrative) (Details) (USD $)	3 Months Ended
Mar. 31, 2013
Construction work in process	$ 39,000,000
Number Of Generating Facilities	7
DP&L [Member]
Construction work in process	31,000,000
Number Of Generating Facilities	7
Hutchings Plant [Member]
Undivided ownership interests	100.00%
Hutchings Plant [Member] \| DP&L [Member]
Undivided ownership interests	100.00%
Beckjord Unit 6 [Member]
Undivided ownership interests	50.00%
Property, Plant, and Equipment, Fair Value Disclosure	$ 0
Beckjord Unit 6 [Member] \| DP&L [Member]
Undivided ownership interests	50.00%

Number Of Generating Facilities

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- Definition

The number of coal-fired generating facilities in which the Company has undivided ownership interests with certain other utilities.

+ References

No definition available.

+ Details

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- Definition

The period end amount of construction work in progress at a jointly owned electricity generation plant.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 360

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 10.C)

-URI http://asc.fasb.org/extlink&oid=6500719&loc=d3e659983-123033

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

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 10

-Section C

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- Definition

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software, net of accumulated depreciation.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 33

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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