Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2017

Related Party Transaction [Line Items]

Schedule of New Accounting Pronouncements

The following table provides a brief description of recent accounting pronouncements that could have a material impact on our consolidated financial statements:

Accounting Standard	Description	Date of Adoption	Effect on the financial statements upon adoption
New Accounting Standards Adopted
2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting	The standard simplifies the following aspects of accounting for share-based payments awards: accounting for income taxes, classification of excess tax benefits on the statement of cash flows, forfeitures, statutory tax withholding requirements, classification of awards as either equity or liabilities and classification of employee taxes paid on statement of cash flows when an employer withholds shares for tax-withholding purposes. Transition method: The recognition of excess tax benefits and tax deficiencies arising from vesting or settlement were applied retrospectively. The elimination of the requirement that excess tax benefits be realized before they are recognized was adopted on a modified retrospective basis with a cumulative adjustment to the opening balance sheet.	January 1, 2017	The primary effect of adoption was the recognition of excess tax benefits in our provision for income taxes in the period when the awards vest or are settled, rather than in paid-in-capital in the period when the excess tax benefits are realized. We will continue to estimate the number of awards that are expected to vest in our determination of the related periodic compensation cost. The adoption of this standard did not have a material impact on the consolidated financial statements.

Accounting Standard	Description	Date of Adoption	Effect on the financial statements upon adoption
New Accounting Standards Issued But Not Yet Effective
2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities	This standard shortens the period of amortization of the premium on certain callable debt securities to the earliest call date. Transition method: modified retrospective.	January 1, 2019. Early adoption is permitted.	We are currently evaluating the impact of adopting the standard on our consolidated financial statements.
2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost	The standard provides guidance on the presentation of net benefit cost in an employer’s income statement and on the components eligible for capitalization. It requires that an employer report the service cost component in the same line item(s) as other employee compensation costs arising from services rendered during the period, and report the other components of net benefit cost separately from the service cost component and outside a subtotal of operating income. Only the service cost component will be eligible for capitalization. Transition method: various.	January 1, 2018. Early adoption is permitted.	We are currently evaluating the impact of adopting the standard on our consolidated financial statements.
2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business	This standard provides guidance to assist the entities with evaluating when a set of transferred assets and activities is a business. Transition method: prospective.	January 1, 2018. Early adoption is permitted	We are currently evaluating the impact of adopting the standard on our consolidated financial statements.
2016-18, Statement of Cash Flows (Topic 320): Restricted Cash (a consensus of the FASB Emerging Issues Task Force)	This standard requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. Transition method: retrospective.	January 1, 2018. Early adoption is permitted	We are currently evaluating the impact of adopting the standard on our consolidated financial statements.
2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory	This standard requires that an entity recognizes the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Transition method: modified retrospective method.	January 1, 2018. Early adoption is permitted.	We are currently evaluating the impact of adopting the standard on our consolidated financial statements.
2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Receipts and Cash Payments (a consensus of the Emerging Issues Task Force)	This standard provides specific guidance on how certain cash transactions are presented and classified in the statement of cash flows. Transition method: retrospective method	January 1, 2018. Early adoption is permitted.	We are currently evaluating the impact of adopting the standard on our consolidated financial statements but do not anticipate a material impact.
2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments	This standard updates the impairment model for financial assets measured at amortized cost to an expected loss model rather than an incurred loss model. It also allows for the presentation of credit losses on available-for-sale debt securities as an allowance rather than a write down. Transition method: various.	January 1, 2020. Early adoption is permitted only as of January 1, 2019.	We are currently evaluating the impact of adopting the standard on our consolidated financial statements.
2016-02, Leases (Topic 842)	The standard creates Topic 842, Leases which supersedes Topic 840, Leases, and introduces a lessee model that brings substantially all leases onto the balance sheet while retaining most of the principles of the existing lessor model in U.S. GAAP and aligning many of those principles with ASC 606, Revenue from Contracts with Customers. Transition method: modified retrospective approach with certain practical expedients.	January 1, 2019. Early adoption is permitted.	We are currently evaluating the impact of adopting the standard on our consolidated financial statements.

Accounting Standard	Description	Date of Adoption	Effect on the financial statements upon adoption
2014-09, 2015-14, 2016-08, 2016-10, 2016-12, 2016-20, 2017-05 Revenue from Contracts with Customers (Topic 606)	See discussion of the ASUs below.	January 1, 2018. Earlier application is permitted only as of January 1, 2017.	We will adopt the standard on January 1, 2018; see below for the evaluation of the impact of its adoption on the consolidated financial statements.

THE DAYTON POWER AND LIGHT COMPANY [Member]

Related Party Transaction [Line Items]

Schedule of New Accounting Pronouncements

The following table provides a brief description of recent accounting pronouncements that could have a material impact on our financial statements:

Accounting Standard	Description	Date of Adoption	Effect on the financial statements upon adoption
New Accounting Standards Adopted
2016-09, Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting	The standard simplifies the following aspects of accounting for share-based payments awards: accounting for income taxes, classification of excess tax benefits on the statement of cash flows, forfeitures, statutory tax withholding requirements, classification of awards as either equity or liabilities and classification of employee taxes paid on statement of cash flows when an employer withholds shares for tax-withholding purposes. Transition method: The recognition of excess tax benefits and tax deficiencies arising from vesting or settlement were applied retrospectively. The elimination of the requirement that excess tax benefits be realized before they are recognized was adopted on a modified retrospective basis with a cumulative adjustment to the opening balance sheet.	January 1, 2017	The primary effect of adoption was the recognition of excess tax benefits in our provision for income taxes in the period when the awards vest or are settled, rather than in paid-in-capital in the period when the excess tax benefits are realized. We will continue to estimate the number of awards that are expected to vest in our determination of the related periodic compensation cost. The adoption of this standard did not have a material impact on the financial statements.
New Accounting Standards Issued But Not Yet Effective
2017-08, Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities	This standard shortens the period of amortization of the premium on certain callable debt securities to the earliest call date. Transition method: modified retrospective.	January 1, 2019. Early adoption is permitted.	We are currently evaluating the impact of adopting the standard on our financial statements.
2017-07, Compensation—Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost	The standard provides guidance on the presentation of net benefit cost in an employer’s income statement and on the components eligible for capitalization. It requires that an employer report the service cost component in the same line item(s) as other employee compensation costs arising from services rendered during the period, and report the other components of net benefit cost separately from the service cost component and outside a subtotal of operating income. Only the service cost component will be eligible for capitalization. Transition method: various.	January 1, 2018. Early adoption is permitted.	We are currently evaluating the impact of adopting the standard on our financial statements.
2017-01, Business Combinations (Topic 805): Clarifying the Definition of a Business	This standard provides guidance to assist the entities with evaluating when a set of transferred assets and activities is a business. Transition method: prospective.	January 1, 2018. Early adoption is permitted	We are currently evaluating the impact of adopting the standard on our financial statements.

Accounting Standard	Description	Date of Adoption	Effect on the financial statements upon adoption
2016-18, Statement of Cash Flows (Topic 320): Restricted Cash (a consensus of the FASB Emerging Issues Task Force)	This standard requires that a statement of cash flows explain the change during the period in the total of cash, cash equivalents, and amounts generally described as restricted cash or restricted cash equivalents. Therefore, amounts generally described as restricted cash and restricted cash equivalents should be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. Transition method: retrospective.	January 1, 2018. Early adoption is permitted	We are currently evaluating the impact of adopting the standard on our financial statements.
2016-16, Income Taxes (Topic 740): Intra-Entity Transfers of Assets Other Than Inventory	This standard requires that an entity recognizes the income tax consequences of an intra-entity transfer of an asset other than inventory when the transfer occurs. Transition method: modified retrospective method.	January 1, 2018. Early adoption is permitted.	We are currently evaluating the impact of adopting the standard on our financial statements.
2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Receipts and Cash Payments (a consensus of the Emerging Issues Task Force)	This standard provides specific guidance on how certain cash transactions are presented and classified in the statement of cash flows. Transition method: retrospective method	January 1, 2018. Early adoption is permitted.	We are currently evaluating the impact of adopting the standard on our financial statements but do not anticipate a material impact.
2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments	This standard updates the impairment model for financial assets measured at amortized cost to an expected loss model rather than an incurred loss model. It also allows for the presentation of credit losses on available-for-sale debt securities as an allowance rather than a write down. Transition method: various.	January 1, 2020. Early adoption is permitted only as of January 1, 2019.	We are currently evaluating the impact of adopting the standard on our financial statements.
2016-02, Leases (Topic 842)	The standard creates Topic 842, Leases which supersedes Topic 840, Leases, and introduces a lessee model that brings substantially all leases onto the balance sheet while retaining most of the principles of the existing lessor model in U.S. GAAP and aligning many of those principles with ASC 606, Revenue from Contracts with Customers. Transition method: modified retrospective approach with certain practical expedients.	January 1, 2019. Early adoption is permitted.	We are currently evaluating the impact of adopting the standard on our financial statements.
2014-09, 2015-14, 2016-08, 2016-10, 2016-12, 2016-20, 2017-05 Revenue from Contracts with Customers (Topic 606)	See discussion of the ASUs below.	January 1, 2018. Earlier application is permitted only as of January 1, 2017.	We will adopt the standard on January 1, 2018; see below for the evaluation of the impact of its adoption on the financial statements.