Pension and Postretirement Benefits (Estimated Future Benefit Payments and Medicare Part D Reimbursements) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015
Pension [Member]
2015	$ 18.6
2016	25.2
2017	25.7
2018	26.3
2019	26.7
2020 - 2024	137.0
Postretirement [Member]
2015	1.4
2016	1.8
2017	1.7
2018	1.6
2019	1.5
2020 - 2024	6.1
DP&L [Member] \| Pension [Member]
2015	18.6
2016	25.7
2017	26.3
2018	26.7
2019	25.2
2020 - 2024	137.0
DP&L [Member] \| Postretirement [Member]
2015	1.4
2016	1.7
2017	1.6
2018	1.5
2019	1.8
2020 - 2024	$ 6.1

Amount of benefits from a defined benefit plan expected to be paid in the five fiscal years after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920

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Amount of benefits from a defined benefit plan expected to be paid in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of benefits from a defined benefit plan expected to be paid in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of benefits from a defined benefit plan expected to be paid in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of benefits from a defined benefit plan expected to be paid in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of benefits from a defined benefit plan expected to be paid in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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