| Cover | Jun. 17, 2020 |
| Condensed Cash Flow Statements, Captions [Line Items] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jun. 17, 2020 |
| Entity File Number | 1-9052 |
| Entity Registrant Name | DPL Inc. |
| Entity Central Index Key | 0000787250 |
| Entity Tax Identification Number | 31-1163136 |
| Entity Incorporation, State or Country Code | OH |
| Entity Address, Address Line One | 1065 Woodman Drive |
| Entity Address, City or Town | Dayton |
| Entity Address, State or Province | OH |
| Entity Address, Postal Zip Code | 45432 |
| City Area Code | 937 |
| Local Phone Number | 259-7215 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Subsidiaries [Member] | |
| Condensed Cash Flow Statements, Captions [Line Items] | |
| Entity File Number | 1-2385 |
| Entity Registrant Name | THE DAYTON POWER AND LIGHT COMPANY |
| Entity Central Index Key | 0000027430 |
| Entity Tax Identification Number | 31-0258470 |
| Entity Incorporation, State or Country Code | OH |
| Entity Address, Address Line One | 1065 Woodman Drive |
| Entity Address, City or Town | Dayton |
| Entity Address, State or Province | OH |
| Entity Address, Postal Zip Code | 45432 |
| City Area Code | 937 |
| Local Phone Number | 259-7215 |
| Entity Emerging Growth Company | false |
