Fixed-asset Impairment (Notes)

9 Months Ended

Sep. 30, 2016

Finite-Lived Intangible Assets [Line Items]

Asset Impairment Charges [Text Block]

Fixed-asset Impairment

During the second quarter of 2016, we tested the recoverability of our long-lived assets at certain of our generation facilities at DP&L. A ruling by the Supreme Court of Ohio on June 20, 2016, lower expectation of future capacity revenue resulting from the most recent PJM capacity auction and a higher anticipated level of environmental compliance costs resulting from third party studies were collectively determined to be an impairment indicator for these assets. We performed a long-lived asset impairment analysis and determined that the carrying amount of Killen and certain DP&L peaking generating facilities were not recoverable. The asset groups of Killen and these DP&L peaking generating facilities were determined to have fair values of $84.3 million and $5.2 million, respectively, using the discounted cash flows under the income approach. As a result, we recognized an asset impairment expense of $230.8 million and $4.7 million for Killen and these DP&L peaking generating facilities, respectively.

THE DAYTON POWER AND LIGHT COMPANY [Member]

Finite-Lived Intangible Assets [Line Items]

Asset Impairment Charges [Text Block]

Fixed-asset Impairment

During the second quarter of 2016, we tested the recoverability of our long-lived assets at certain of our generation facilities at DP&L. A ruling by the Supreme Court of Ohio on June 20, 2016, lower expectation of future capacity revenue resulting from the most recent PJM capacity auction and a higher anticipated level of environmental compliance costs resulting from third party studies were collectively determined to be an impairment indicator for these assets. We performed a long-lived asset impairment test and determined that the carrying amounts of the asset groups of Stuart, Killen and Zimmer were not recoverable. The asset groups of Stuart, Killen and Zimmer were determined to have fair values of $164.4 million, $84.3 million and $111.0 million, respectively, using the discounted cash flows under the income approach. As a result, we recognized asset impairment expenses of $292.0 million, $246.2 million and $318.9 million for Stuart, Killen and Zimmer, respectively during the nine months ended September 30, 2016.