Benefit Plans (Weighted Average Assumptions Used to Determine Benefit Obligations) (Details) - Pension [Member]	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Discount rate for obligations	2.83%	2.44%	3.33%
Rate of compensation increases	3.21%	3.21%	3.94%
THE DAYTON POWER AND LIGHT COMPANY [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate for obligations	2.83%	2.44%	3.33%
Rate of compensation increases	3.21%	3.21%	3.94%