Regulated Matters (Narrative Details) - USD ($) $ in Millions				12 Months Ended	60 Months Ended
	Nov. 29, 2024	Apr. 10, 2023	Dec. 14, 2022	Dec. 31, 2024	Sep. 30, 2028	Jul. 01, 2025
Regulatory Asset [Line Items]
RSC Rider				$ 79.0
Revenue Increase - Distribution Rate Case	$ 235.2		$ 75.6
Return on Equity - Distribution Rate Case	10.95%		9.999%
Cost of Long-term Debt - Distribution Rate Case	4.49%		4.40%
Rate Base - Distribution Rate Case	$ 1,300.0		$ 783.5
Capital Structure - Equity - Distribution Rate Case	53.87%		53.87%
Capital Structure - Long-term Debt - Distribution Rate Case	46.13%		46.13%
Return on Equity SEET Threshold				9.85%
Maximum Regulatory compliance cost to be accrued					$ 4.0
DRO Vegetation Management Cost Baseline				$ 20.0
DRO Vegetation Management Cost Deferral Cap				7.5
Maximum CIS Replacement cost deferral				8.8
Customer Program Costs				0.3
Customer Program Costs - Residential Low Income Assistance				5.7
Regulatory assets earning a return				16.2
THE DAYTON POWER AND LIGHT COMPANY [Member]
Regulatory Asset [Line Items]
RSC Rider				79.0
Return on Equity - ESP 4		9.999%
Recovery - ESP 4		$ 66.0
Deferral of Purchased Power Costs - ESP 4				28.3
Deferral of Carrying Costs - ESP 4				$ 10.7
Revenue Increase - Distribution Rate Case	$ 235.2		$ 75.6
Return on Equity - Distribution Rate Case	10.95%		9.999%
Cost of Long-term Debt - Distribution Rate Case	4.49%		4.40%
Rate Base - Distribution Rate Case	$ 1,300.0		$ 783.5
Capital Structure - Equity - Distribution Rate Case	53.87%		53.87%
Capital Structure - Long-term Debt - Distribution Rate Case	46.13%		46.13%
Return on Equity SEET Threshold				9.85%
Maximum Regulatory compliance cost to be accrued					$ 4.0
DRO Vegetation Management Cost Baseline				$ 20.0
DRO Vegetation Management Cost Deferral Cap				7.5
Maximum CIS Replacement cost deferral				8.8
Customer Program Costs				0.3
Customer Program Costs - Residential Low Income Assistance				5.7
TCJA Yearly Refund to Customers Per DRO				4.0
Regulatory assets earning a return				16.2
Forecast [Member]
Regulatory Asset [Line Items]
Estimated Smart Grid Phase 2 capital						$ 240.5
Estimated Smart Grid Phase 2 O&M						$ 18.6
TCJA Yearly Refund to Customers Per DRO				$ 4.0