2.2.0.25truefalse0020 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWStruefalseIn Millionsfalse1falsefalseUSDfalsefalse1/1/2011 - 3/31/2011 USD ($) USD ($) / shares $D2011Q1http://www.sec.gov/CIK0000787250duration2011-01-01T00:00:002011-03-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2falsefalseUSDfalsefalse1/1/2010 - 3/31/2010 USD ($) USD ($) / shares $D2010Q1http://www.sec.gov/CIK0000787250duration2010-01-01T00:00:002010-03-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2true0us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringThe net cash from (used in) all of the entity's operating activities, including those of discontinued operations, of the reporting entity. Operating activities include all transactions and events that are not defined as investing or financing activities. Operating activities generally involve producing and delivering goods and providing services. Cash flows from operating activities are generally the cash effects of transactions and other events that enter into the determination of net income.falsefalseCash flows from operating activities:3false0us-gaap_ProfitLossus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse4350000043.5falsetruefalsefalsefalse2truefalsefalse7100000071.0falsetruefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A1, A4, A5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 5 -Subparagraph b Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(1) falsefalseNet income4true0us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseAdjustments to reconcile Net income to Net cash provided by operating activities:5false0us-gaap_DepreciationDepletionAndAmortizationus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse3510000035.1falsefalsefalsefalsefalse2truefalsefalse3740000037.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.No authoritative reference available.falsefalseDepreciation and amortization6false0us-gaap_DeferredIncomeTaxExpenseBenefitus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse3370000033.7falsefalsefalsefalsefalse2truefalsefalse1050000010.5falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe component of income tax expense for the period representing the net change in the entity's deferred tax assets and liabilities pertaining to continuing operations.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 6 -Section I -Subsection 7 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 45 -Subparagraph b Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 289 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Article 4 falsefalseDeferred income taxes7false0dpl_IncreaseDecreaseDeferredInvestmentTaxCreditdplfalsedebitdurationThe net change in the noncurrent portion of the reserve for accumulated deferred investment tax credits as of the balance...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-700000-0.7falsefalsefalsefalsefalse2truefalsefalse-700000-0.7falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change in the noncurrent portion of the reserve for accumulated deferred investment tax credits as of the balance sheet date. This is the remaining investment credit, which will reduce the cost of services collected from ratepayers by a ratable portion over the investment's regulatory life.No authoritative reference available.falsefalseUnamortized investment tax credit8false0us-gaap_GainsLossesOnExtinguishmentOfDebtus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse1530000015.3falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryAmount represents the difference between the fair value of the payments made and the carrying amount of the debt at the time of its extinguishment.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 26 -Paragraph 20, 21 falsefalseCharge for early redemption of debt9true0us-gaap_IncreaseDecreaseInOperatingCapitalAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseChanges in certain assets and liabilities:10false0us-gaap_IncreaseDecreaseInReceivablesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse1190000011.9falsefalsefalsefalsefalse2truefalsefalse-3100000-3.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the total amount due within one year (or one operating cycle) from all parties, associated with underlying transactions that are classified as operating activities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseAccounts receivable11false0us-gaap_IncreaseDecreaseInInventoriesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse4000000.4falsefalsefalsefalsefalse2truefalsefalse30000003.0falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the aggregate value of all inventory held by the reporting entity, associated with underlying transactions that are classified as operating activities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseInventories12false0dpl_IncreaseDecreaseInTaxesApplicableToSubsequentYearsdplfalsecreditdurationThe net change during the reporting period in the aggregate value of capitalized property and other taxes, associated with...falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse1590000015.9falsefalsefalsefalsefalse2truefalsefalse1490000014.9falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the aggregate value of capitalized property and other taxes, associated with underlying transactions that are classified as operating activities.No authoritative reference available.falsefalseTaxes applicable to subsequent years13false0us-gaap_IncreaseDecreaseInRegulatoryAssetsAndLiabilitiesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse1280000012.8falsefalsefalsefalsefalse2truefalsefalse-2500000-2.5falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the value of assets that are created when regulatory agencies permits public utilities to defer costs (revenues) to the balance sheet. This element is a the net change of regulatory assets and liabilities combined.No authoritative reference available.falsefalseDeferred regulatory costs, net14false0us-gaap_IncreaseDecreaseInAccountsPayableus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-5100000-5.1falsefalsefalsefalsefalse2truefalsefalse64000006.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the aggregate amount of obligations due within one year (or one business cycle). This may include trade payables, amounts due to related parties, royalties payable, and other obligations.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseAccounts payable15false0us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayableus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-28400000-28.4falsefalsefalsefalsefalse2truefalsefalse-800000-0.8falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the period in the amount of cash payments due to taxing authorities for taxes that are based on the reporting entity's earnings.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseAccrued taxes payable16false0us-gaap_IncreaseDecreaseInInterestPayableNetus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-1200000-1.2falsefalsefalsefalsefalse2truefalsefalse-5600000-5.6falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in interest payable, which represents the amount owed to note holders, bond holders, and other parties for interest earned on loans or credit extended to the reporting entity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseAccrued interest payable17false0us-gaap_IncreaseDecreaseInPensionAndPostretirementObligationsus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-41200000-41.2falsefalsefalsefalsefalse2truefalsefalse-21100000-21.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the amount due to fund pension and non-pension benefits to employees, retired and disabled former employees.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalsePension, retiree and other benefits18false0dpl_IncreaseDecreaseInSelfInsuranceReservedplfalsedebitdurationThe net change during the reporting period in the carrying amount of accrued known and estimated losses incurred as of the...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse22000002.2falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the carrying amount of accrued known and estimated losses incurred as of the balance sheet date for which no insurance coverage exists.No authoritative reference available.falsefalseInsurance and claims costs19false0us-gaap_IncreaseDecreaseInOtherOperatingCapitalNetus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-2200000-2.2falsefalsefalsefalsefalse2truefalsefalse1320000013.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryFor entities with classified balance sheets, the net change during the reporting period in the value of other assets or liabilities used in operating activities, that are not otherwise defined in the taxonomy. For entities with unclassified balance sheets, the net change during the reporting period in the value of all other assets or liabilities used in operating activities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseOther20false0us-gaap_NetCashProvidedByUsedInOperatingActivitiesus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse9200000092.0falsefalsefalsefalsefalse2truefalsefalse122600000122.6falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net cash from (used in) all of the entity's operating activities, including those of discontinued operations, of the reporting entity. Operating activities generally involve producing and delivering goods and providing services. Operating activity cash flows include transactions, adjustments, and changes in value that are not defined as investing or financing activities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 26 truefalseNet cash provided by operating activities21true0us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseCash flows from investing activities:22false0us-gaap_PaymentsToAcquireProductiveAssetsus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-43000000-43.0falsefalsefalsefalsefalse2truefalsefalse-39800000-39.8falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 15 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 17 -Subparagraph c falsefalseCapital expenditures23false0us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquiredus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-8200000-8.2falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 15, 17 falsefalsePurchase of MC Squared24false0us-gaap_PaymentsToAcquireShortTermInvestmentsus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-1700000-1.7falsefalsefalsefalsefalse2truefalsefalse-33700000-33.7falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow for securities or other assets acquired with excess cash, having ready marketability, which qualify for treatment as an investing activity based on management's intention and intended by management to be liquidated, if necessary, within the current operating cycle. Includes cash flows from securities classified as trading securities that were acquired for reasons other than sale in the short-term.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 15, 17 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 159 -Section Appendix C -Paragraph 5 -Subparagraph c falsefalsePurchases of short-term investments and securities25false0us-gaap_ProceedsFromSaleOfShortTermInvestmentsus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse6080000060.8falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash inflow from securities or other assets sold, having ready marketability and intended by management to be liquidated, if necessary, within the current operating cycle. Includes cash flows from securities classified as trading securities that were acquired for reasons other than sale in the short-term.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 159 -Section Appendix C -Paragraph 5 -Subparagraph c Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 15, 16 falsefalseSales of short-term investments and securities26false0us-gaap_PaymentsForProceedsFromOtherInvestingActivitiesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse21000002.1falsefalsefalsefalsefalse2truefalsefalse22000002.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net cash outflow (inflow) from other investing activities. This element is used when there is not a more specific and appropriate element in the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 15 falsefalseOther27false0us-gaap_NetCashProvidedByUsedInInvestingActivitiesus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse1000000010.0falsefalsefalsefalsefalse2truefalsefalse-71300000-71.3falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net cash inflow (outflow) from investing activity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 26 truefalseNet cash provided by / used for investing activities28true0us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseCash flows from financing activities:29false0us-gaap_PaymentsOfDividendsCommonStockus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-37800000-37.8falsefalsefalsefalsefalse2truefalsefalse-35000000-35.0falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow from the distribution of an entity's earnings in the form of dividends to common shareholders.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 20 -Subparagraph a falsefalseDividends paid on common stock30false0us-gaap_RepaymentsOfOtherLongTermDebtus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-122000000-122.0falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow for borrowing not otherwise defined in the taxonomy (with maturities initially due after one year or beyond the operating cycle if longer).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 20 -Subparagraph b falsefalseEarly redemption of Capital Trust II debt31false0us-gaap_ProceedsFromPaymentsForOtherFinancingActivitiesus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-12200000-12.2falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net cash inflow (outflow) from other financing activities. This element is used when there is not a more specific and appropriate element in the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18, 19, 20 falsefalsePremium paid for early redemption of debt32false0us-gaap_RepaymentsOfRelatedPartyDebtus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-13500000-13.5falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow for the payment of borrowing made from related party where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 20 -Subparagraph b falsefalsePayment of MC Squared debt33false0us-gaap_ProceedsFromLinesOfCreditus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse5000000050.0falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash inflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with either short term or long term maturity that is collateralized (backed by pledge, mortgage or other lien in the entity's assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 19 -Subparagraph b falsefalseWithdrawals from revolving credit facilities34false0us-gaap_RepaymentsOfLinesOfCreditus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-20000000-20.0falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow to pay off an obligation from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with either short term or long term maturity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 20 -Subparagraph b falsefalseRepayment of borrowing from revolving credit facilities35false0us-gaap_PaymentsForRepurchaseOfCommonStockus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse-3900000-3.9falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow to reacquire common stock during the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 20 -Subparagraph a falsefalseRepurchase of DPL common stock36false0dpl_ProceedsFromOtherFinancingActivitiesdplfalsedebitdurationThe cash inflow from other financing activities. This element is used when there is not a more specific and appropriate...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse16000001.6falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash inflow from other financing activities. This element is used when there is not a more specific and appropriate element in the taxonomy.No authoritative reference available.falsefalseOther37false0us-gaap_NetCashProvidedByUsedInFinancingActivitiesus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse-155500000-155.5falsefalsefalsefalsefalse2truefalsefalse-37300000-37.3falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net cash inflow (outflow) from financing activity for the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 26 truefalseNet cash used for financing activities38true0us-gaap_CashAndCashEquivalentsAtCarryingValueAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseCash and cash equivalents:39false0us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse-53500000-53.5falsefalsefalsefalsefalse2truefalsefalse1400000014.0falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change between the beginning and ending balance of cash and cash equivalents.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 26 truefalseNet change40false0us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsetruefalsefalseperiodstartlabel1truefalsefalse124000000124.0falsefalsefalsefalsefalse2truefalsefalse7490000074.9falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryIncludes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits should not be reported as cash and cash equivalents.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 7, 26 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 8, 9 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 7 -Footnote 1 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 1 -Article 5 falsefalseBalance at beginning of period41false0us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsetruefalseperiodendlabel1truefalsefalse7050000070.5falsefalsefalsefalsefalse2truefalsefalse8890000088.9falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryIncludes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits should not be reported as cash and cash equivalents.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 7, 26 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 8, 9 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 7 -Footnote 1 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 1 -Article 5 falsefalseCash and cash equivalents at end of period42true0us-gaap_SupplementalCashFlowInformationAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseSupplemental cash flow information:43false0us-gaap_InterestPaidNetus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse1810000018.1falsefalsefalsefalsefalse2truefalsefalse2370000023.7falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount of cash paid during the current period for interest owed on money borrowed, net of interest capitalized.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 29 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 27 -Subparagraph e falsefalseInterest paid, net of amounts capitalized44false0us-gaap_IncomeTaxesPaidNetus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse51000005.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 29 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 27 -Subparagraph f falsefalseIncome taxes refunded, net45true0us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringDesignated to encapsulate the entire footnote disclosure that gives information on the supplemental cash flow activities for noncash (or part noncash) transactions for the period. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.falsefalseNon-cash financing and investing activities:46false0us-gaap_CapitalExpendituresIncurredButNotYetPaidus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse1830000018.3falsefalsefalsefalsefalse2truefalsefalse1330000013.3falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryFuture cash outflow to pay for purchases of fixed assets that have occurred.No authoritative reference available.falsefalseAccruals for capital expenditures47false0dpl_CapitalExpendituresIncurredButNotYetPaidLongTermdplfalsecreditdurationLong term obligation related to future cash outflow to pay for purchases of fixed assets that have occurred.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse1870000018.7falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryLong term obligation related to future cash outflow to pay for purchases of fixed assets that have occurred.No authoritative reference available.falsefalseLong-term liability incurred for purchase of assets48false0natruenanaNo definition available.falsetruefalsefalsefalsefalsefalsefalsefalsefalsehttp://www.dplinc.com/role/cashflows1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalse3falsefalseUSDtruefalse{dei_LegalEntityAxis} : THE DAYTON POWER AND LIGHT COMPANY 1/1/2011 - 3/31/2011 USD ($) $D2011Q1_SubsidiariesMemberhttp://www.sec.gov/CIK0000787250duration2011-01-01T00:00:002011-03-31T00:00:00falsefalseTHE DAYTON POWER AND LIGHT COMPANYdei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_SubsidiariesMemberdei_LegalEntityAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDUSD$4falsefalseUSDtruefalse{dei_LegalEntityAxis} : THE DAYTON POWER AND LIGHT COMPANY 1/1/2010 - 3/31/2010 USD ($) $D2010Q1_SubsidiariesMemberhttp://www.sec.gov/CIK0000787250duration2010-01-01T00:00:002010-03-31T00:00:00falsefalseTHE DAYTON POWER AND LIGHT COMPANYdei_LegalEntityAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_SubsidiariesMemberdei_LegalEntityAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$OthernaNo definition available.No authoritative reference available.falsefalseTHE DAYTON POWER AND LIGHT COMPANY49true0us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringThe net cash from (used in) all of the entity's operating activities, including those of discontinued operations, of the reporting entity. Operating activities include all transactions and events that are not defined as investing or financing activities. Operating activities generally involve producing and delivering goods and providing services. Cash flows from operating activities are generally the cash effects of transactions and other events that enter into the determination of net income.falsefalseCash flows from operating activities:50false0us-gaap_ProfitLossus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse5270000052.7falsefalsefalsefalsefalse2truefalsefalse7210000072.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A1, A4, A5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 5 -Subparagraph b Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(1) falsefalseNet income51true0us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseAdjustments to reconcile Net income to Net cash provided by operating activities:52false0us-gaap_DepreciationDepletionAndAmortizationus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse3310000033.1falsefalsefalsefalsefalse2truefalsefalse3480000034.8falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.No authoritative reference available.falsefalseDepreciation and amortization53false0us-gaap_DeferredIncomeTaxExpenseBenefitus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse3330000033.3falsefalsefalsefalsefalse2truefalsefalse99000009.9falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe component of income tax expense for the period representing the net change in the entity's deferred tax assets and liabilities pertaining to continuing operations.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 6 -Section I -Subsection 7 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 45 -Subparagraph b Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 289 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Article 4 falsefalseDeferred income taxes54false0dpl_IncreaseDecreaseDeferredInvestmentTaxCreditdplfalsedebitdurationThe net change in the noncurrent portion of the reserve for accumulated deferred investment tax credits as of the balance...falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-700000-0.7falsefalsefalsefalsefalse2truefalsefalse-700000-0.7falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change in the noncurrent portion of the reserve for accumulated deferred investment tax credits as of the balance sheet date. This is the remaining investment credit, which will reduce the cost of services collected from ratepayers by a ratable portion over the investment's regulatory life.No authoritative reference available.falsefalseUnamortized investment tax credit55true0us-gaap_IncreaseDecreaseInOperatingCapitalAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseChanges in certain assets and liabilities:56false0us-gaap_IncreaseDecreaseInReceivablesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse1190000011.9falsefalsefalsefalsefalse2truefalsefalse47000004.7falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the total amount due within one year (or one operating cycle) from all parties, associated with underlying transactions that are classified as operating activities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseAccounts receivable57false0us-gaap_IncreaseDecreaseInInventoriesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse4000000.4falsefalsefalsefalsefalse2truefalsefalse27000002.7falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the aggregate value of all inventory held by the reporting entity, associated with underlying transactions that are classified as operating activities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseInventories58false0dpl_IncreaseDecreaseInTaxesApplicableToSubsequentYearsdplfalsecreditdurationThe net change during the reporting period in the aggregate value of capitalized property and other taxes, associated with...falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse1570000015.7falsefalsefalsefalsefalse2truefalsefalse1480000014.8falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the aggregate value of capitalized property and other taxes, associated with underlying transactions that are classified as operating activities.No authoritative reference available.falsefalseTaxes applicable to subsequent years59false0us-gaap_IncreaseDecreaseInRegulatoryAssetsAndLiabilitiesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse1280000012.8falsefalsefalsefalsefalse2truefalsefalse-2500000-2.5falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the value of assets that are created when regulatory agencies permits public utilities to defer costs (revenues) to the balance sheet. This element is a the net change of regulatory assets and liabilities combined.No authoritative reference available.falsefalseDeferred regulatory costs, net60false0us-gaap_IncreaseDecreaseInAccountsPayableus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-4000000-4.0falsefalsefalsefalsefalse2truefalsefalse60000006.0falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the aggregate amount of obligations due within one year (or one business cycle). This may include trade payables, amounts due to related parties, royalties payable, and other obligations.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseAccounts payable61false0us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayableus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-28900000-28.9falsefalsefalsefalsefalse2truefalsefalse5000000.5falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the period in the amount of cash payments due to taxing authorities for taxes that are based on the reporting entity's earnings.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseAccrued taxes payable62false0us-gaap_IncreaseDecreaseInInterestPayableNetus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse76000007.6falsefalsefalsefalsefalse2truefalsefalse22000002.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in interest payable, which represents the amount owed to note holders, bond holders, and other parties for interest earned on loans or credit extended to the reporting entity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseAccrued interest payable63false0us-gaap_IncreaseDecreaseInPensionAndPostretirementObligationsus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse-41200000-41.2falsefalsefalsefalsefalse2truefalsefalse-21100000-21.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change during the reporting period in the amount due to fund pension and non-pension benefits to employees, retired and disabled former employees.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalsePension, retiree and other benefits64false0us-gaap_IncreaseDecreaseInOtherOperatingCapitalNetus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-8700000-8.7falsefalsefalsefalsefalse2truefalsefalse1140000011.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryFor entities with classified balance sheets, the net change during the reporting period in the value of other assets or liabilities used in operating activities, that are not otherwise defined in the taxonomy. For entities with unclassified balance sheets, the net change during the reporting period in the value of all other assets or liabilities used in operating activities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 falsefalseOther65false0us-gaap_NetCashProvidedByUsedInOperatingActivitiesus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse8400000084.0falsefalsefalsefalsefalse2truefalsefalse134800000134.8falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net cash from (used in) all of the entity's operating activities, including those of discontinued operations, of the reporting entity. Operating activities generally involve producing and delivering goods and providing services. Operating activity cash flows include transactions, adjustments, and changes in value that are not defined as investing or financing activities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 26 truefalseNet cash provided by operating activities66true0us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseCash flows from investing activities:67false0us-gaap_PaymentsToAcquireProductiveAssetsus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-42400000-42.4falsefalsefalsefalsefalse2truefalsefalse-39400000-39.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 15 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 17 -Subparagraph c falsefalseCapital expenditures68false0us-gaap_PaymentsForProceedsFromOtherInvestingActivitiesus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse20000002.0falsefalsefalsefalsefalse2truefalsefalse22000002.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net cash outflow (inflow) from other investing activities. This element is used when there is not a more specific and appropriate element in the taxonomy.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 15 falsefalseOther69false0us-gaap_NetCashProvidedByUsedInInvestingActivitiesus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse-40400000-40.4falsefalsefalsefalsefalse2truefalsefalse-37200000-37.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net cash inflow (outflow) from investing activity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 26 truefalseNet cash provided by / used for investing activities70true0us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseCash flows from financing activities:71false0us-gaap_PaymentsOfDividendsCommonStockus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-70000000-70.0falsefalsefalsefalsefalse2truefalsefalse-90000000-90.0falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow from the distribution of an entity's earnings in the form of dividends to common shareholders.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 20 -Subparagraph a falsefalseDividends paid on common stock72false0us-gaap_PaymentsOfDividendsPreferredStockAndPreferenceStockus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-200000-0.2falsefalsefalsefalsefalse2truefalsefalse-200000-0.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow for the return on capital for preferred shareholders.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 20 -Subparagraph a falsefalseDividends paid on preferred stock73false0us-gaap_ProceedsFromLinesOfCreditus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse5000000050.0falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash inflow from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with either short term or long term maturity that is collateralized (backed by pledge, mortgage or other lien in the entity's assets).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 19 -Subparagraph b falsefalseWithdrawals from revolving credit facilities74false0us-gaap_RepaymentsOfLinesOfCreditus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsetruenegated1truefalsefalse-20000000-20.0falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe cash outflow to pay off an obligation from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with either short term or long term maturity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 20 -Subparagraph b falsefalseRepayment of borrowing from revolving credit facilities75false0us-gaap_NetCashProvidedByUsedInFinancingActivitiesus-gaaptruedebitdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse-40200000-40.2falsefalsefalsefalsefalse2truefalsefalse-90200000-90.2falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net cash inflow (outflow) from financing activity for the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 26 truefalseNet cash used for financing activities76true0us-gaap_CashAndCashEquivalentsAtCarryingValueAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseCash and cash equivalents:77false0us-gaap_CashAndCashEquivalentsPeriodIncreaseDecreaseus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalsetotallabel1truefalsefalse34000003.4falsefalsefalsefalsefalse2truefalsefalse74000007.4falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe net change between the beginning and ending balance of cash and cash equivalents.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 26 truefalseNet change78false0us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsetruefalsefalseperiodstartlabel1truefalsefalse5400000054.0falsefalsefalsefalsefalse2truefalsefalse5710000057.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryIncludes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits should not be reported as cash and cash equivalents.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 7, 26 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 8, 9 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 7 -Footnote 1 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 1 -Article 5 falsefalseBalance at beginning of period79false0us-gaap_CashAndCashEquivalentsAtCarryingValueus-gaaptruedebitinstantNo definition available.falsefalsefalsefalsefalsefalsefalsefalsetruefalseperiodendlabel1truefalsefalse5740000057.4falsefalsefalsefalsefalse2truefalsefalse6450000064.5falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryIncludes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Entity may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Compensating balance arrangements that do not legally restrict the withdrawal or usage of cash amounts may be reported as Cash and Cash Equivalents, while legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or company statements of intention with regard to particular deposits should not be reported as cash and cash equivalents.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 7, 26 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 8, 9 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 7 -Footnote 1 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 1 -Article 5 falsefalseCash and cash equivalents at end of period80true0us-gaap_SupplementalCashFlowInformationAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseSupplemental cash flow information:81false0us-gaap_InterestPaidNetus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse23000002.3falsefalsefalsefalsefalse2truefalsefalse76000007.6falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount of cash paid during the current period for interest owed on money borrowed, net of interest capitalized.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 29 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 27 -Subparagraph e falsefalseInterest paid, net of amounts capitalized82false0us-gaap_IncomeTaxesPaidNetus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2truefalsefalse51000005.1falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryThe amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 29 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 27 -Subparagraph f falsefalseIncome taxes refunded, net83true0us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstractus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00falsefalsefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringDesignated to encapsulate the entire footnote disclosure that gives information on the supplemental cash flow activities for noncash (or part noncash) transactions for the period. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.falsefalseNon-cash financing and investing activities:84false0us-gaap_CapitalExpendituresIncurredButNotYetPaidus-gaaptruecreditdurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse1830000018.3falsefalsefalsefalsefalse2truefalsefalse1330000013.3falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryFuture cash outflow to pay for purchases of fixed assets that have occurred.No authoritative reference available.falsefalseAccruals for capital expenditures85false0dpl_CapitalExpendituresIncurredButNotYetPaidLongTermdplfalsecreditdurationLong term obligation related to future cash outflow to pay for purchases of fixed assets that have occurred.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1truefalsefalse1870000018.7falsetruefalsefalsefalse2falsefalsefalse00falsefalsefalsefalsefalseMonetaryxbrli:monetaryItemTypemonetaryLong term obligation related to future cash outflow to pay for purchases of fixed assets that have occurred.No authoritative reference available.falsefalseLong-term liability incurred for purchase of assets284CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)HundredThousandsUnKnownUnKnownUnKnownfalsetrue