Summary of Significant Accounting Policies (Recently Issued Accounting Standards) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015
Deferred Financing costs to be reclassed and deducted from debt amount	$ 20.5
DP&L [Member]
Deferred Financing costs to be reclassed and deducted from debt amount	$ 10.4

This is the amount of Deferred Financing costs that will be reclassed from other non-current assets to reduce the amount of debt liabilities. This is as a result of ASU 2015-03 issued by FASB in April 2015. The standard is effective for annual reporting beginning December, 15, 2015

No definition available.

Name:	dpl_DeferredFinancingCostsThatWillBeReclassedAndDeductedFromDebtAmount
Namespace Prefix:	dpl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration