XML 84 R61.htm IDEA: XBRL DOCUMENT v3.25.0.1
Benefit Plans (Fair Value Measurements for Pension Plan Assets) (Details) - Pension [Member] - USD ($)
$ in Millions
Dec. 31, 2024
Dec. 31, 2023
Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets $ 260.1 $ 268.4 $ 274.4
Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 1.7 1.8  
Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 258.4 266.6  
Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 0.0 0.0  
Defined Benefit Plan, Common Collective Trust      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 258.4 266.6  
Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 0.0 0.0  
Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 258.4 266.6  
Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 0.0 0.0  
THE DAYTON POWER AND LIGHT COMPANY [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 260.1 268.4 $ 274.4
THE DAYTON POWER AND LIGHT COMPANY [Member] | Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 1.7 1.8  
THE DAYTON POWER AND LIGHT COMPANY [Member] | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 258.4 266.6  
THE DAYTON POWER AND LIGHT COMPANY [Member] | Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 0.0 0.0  
THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 258.4 266.6  
THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 0.0 0.0  
THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 258.4 266.6  
THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Pension Plan Assets 0.0 0.0  
Debt Securities [Member] | Defined Benefit Plan, Common Collective Trust      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 118.9 121.1  
Debt Securities [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
Debt Securities [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 118.9 121.1  
Debt Securities [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
Debt Securities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 118.9 121.1  
Debt Securities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
Debt Securities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 118.9 121.1  
Debt Securities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
U.S. Equities [Member] | Defined Benefit Plan, Common Collective Trust      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 81.3 84.5  
U.S. Equities [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
U.S. Equities [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 81.3 84.5  
U.S. Equities [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
U.S. Equities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 81.3 84.5  
U.S. Equities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
U.S. Equities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 81.3 84.5  
U.S. Equities [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
Cash and Cash Equivalents [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 1.7 1.8  
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 1.7 1.8  
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
Cash and Cash Equivalents [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 1.7 1.8  
Cash and Cash Equivalents [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 1.7 1.8  
Cash and Cash Equivalents [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
Cash and Cash Equivalents [Member] | THE DAYTON POWER AND LIGHT COMPANY [Member] | Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
US Government Debt Securities | Defined Benefit Plan, Common Collective Trust      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 58.2 61.0  
US Government Debt Securities | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
US Government Debt Securities | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 58.2 61.0  
US Government Debt Securities | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
US Government Debt Securities | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 58.2 61.0  
US Government Debt Securities | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 1 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 0.0 0.0  
US Government Debt Securities | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 2 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities 58.2 61.0  
US Government Debt Securities | THE DAYTON POWER AND LIGHT COMPANY [Member] | Defined Benefit Plan, Common Collective Trust | Fair Value, Inputs, Level 3 [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Total Equity Securities $ 0.0 $ 0.0