Equity (Preferred Shares Outstanding) (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Temporary Equity [Line Items]
Shares Outstanding		228,508
Carrying Value	$ 0.0	$ 18.4
THE DAYTON POWER AND LIGHT COMPANY [Member]
Temporary Equity [Line Items]
Par Value	$ 0.0	$ 22.9
DP&L Series A [Member]
Temporary Equity [Line Items]
Temporary Equity, Preferred Stock Rate	3.75%	3.75%
Temporary Equity, Redemption Price Per Share	$ 102.50	$ 102.50
Shares Outstanding		93,280
Carrying Value	$ 0.0	$ 7.4
DP&L Series A [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Temporary Equity [Line Items]
Temporary Equity, Preferred Stock Rate	3.75%	3.75%
Temporary Equity, Redemption Price Per Share	$ 102.50	$ 102.50
Shares Outstanding		93,280
Par Value	$ 0.0	$ 9.3
DP&L Series B [Member]
Temporary Equity [Line Items]
Temporary Equity, Preferred Stock Rate	3.75%	3.75%
Temporary Equity, Redemption Price Per Share	$ 103.00	$ 103.00
Shares Outstanding		69,398
Carrying Value	$ 0.0	$ 5.6
DP&L Series B [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Temporary Equity [Line Items]
Temporary Equity, Preferred Stock Rate	3.75%	3.75%
Temporary Equity, Redemption Price Per Share	$ 103.00	$ 103.00
Shares Outstanding		69,398
Par Value	$ 0.0	$ 7.0
DP&L Series C [Member]
Temporary Equity [Line Items]
Temporary Equity, Preferred Stock Rate	3.90%	3.90%
Temporary Equity, Redemption Price Per Share	$ 101.00	$ 101.00
Shares Outstanding		65,830
Carrying Value	$ 0.0	$ 5.4
DP&L Series C [Member] \| THE DAYTON POWER AND LIGHT COMPANY [Member]
Temporary Equity [Line Items]
Temporary Equity, Preferred Stock Rate	3.90%	3.90%
Temporary Equity, Redemption Price Per Share	$ 101.00	$ 101.00
Shares Outstanding		65,830
Par Value	$ 0.0	$ 6.6

Temporary Equity, Preferred Stock Rate

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- Definition

Carrying amount, attributable to parent and noncontrolling interests, of an entity's issued and outstanding stock which is not included within permanent equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. Includes stock with a put option held by an ESOP and stock redeemable by a holder only in the event of a change in control of the issuer.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount to be paid per share that is classified as temporary equity by entity upon redemption. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=27011957&loc=d3e177068-122764

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (27)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

The number of securities classified as temporary equity that have been issued and are held by the entity's shareholders. Securities outstanding equals securities issued minus securities held in treasury. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.27(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 28
-Subparagraph b
-Article 5

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- Definition

Carrying amount of the par value of temporary equity outstanding. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (27)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 480
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=27011957&loc=d3e177068-122764

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