Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2023

Entity Information [Line Items]

Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis

The following table presents the carrying amount, fair value, and fair value hierarchy of our financial liabilities that are not measured at fair value in the Consolidated Balance Sheets as of the periods indicated, but for which fair value is disclosed:

	Carrying Amount		Fair Value at December 31, 2023								Carrying Amount		Fair Value at December 31, 2022
$ in millions			Level 1		Level 2		Level 3		Total				Level 1		Level 2		Level 3		Total
Liabilities
Long-term debt	$	1,837.6	$	—	$	1,706.2	$	16.8	$	1,723.0	$	1,535.9	$	—	$	1,376.4	$	17.0	$	1,393.4

Fair Value, Assets Measured on Recurring Basis

The fair value of assets at December 31, 2023 and 2022 and the respective category within the fair value hierarchy for DPL was determined as follows:

$ in millions	Fair Value at December 31, 2023								Fair Value at December 31, 2022
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Assets
Master trust assets
Money market funds	$	0.6	$	—	$	—	$	0.6	$	0.5	$	—	$	—	$	0.5
Mutual funds	7.2		—		—		7.2		7.0		—		—		7.0
Total assets	$	7.8	$	—	$	—	$	7.8	$	7.5	$	—	$	—	$	7.5

THE DAYTON POWER AND LIGHT COMPANY [Member]

Entity Information [Line Items]

Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis

The following table presents the carrying amount, fair value, and fair value hierarchy of our financial liabilities that are not measured at fair value in the Balance Sheets as of the periods indicated, but for which fair value is disclosed:

	Carrying Amount		Fair Value at December 31, 2023								Carrying Amount		Fair Value at December 31, 2022
$ in millions			Level 1		Level 2		Level 3		Total				Level 1		Level 2		Level 3		Total
Liabilities
Long-term debt	$	1,012.5	$	—	$	909.9	$	16.8	$	926.7	$	712.7	$	—	$	610.9	$	17.0	$	627.9

Fair Value, Assets Measured on Recurring Basis

The fair value of assets at December 31, 2023 and 2022 and the respective category within the fair value hierarchy for AES Ohio was determined as follows:

$ in millions	Fair Value at December 31, 2023								Fair Value at December 31, 2022
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Assets
Money market funds	$	0.6	$	—	$	—	$	0.6	$	0.5	$	—	$	—	$	0.5
Mutual funds	7.2		—		—		7.2		7.0		—		—		7.0
Total assets	$	7.8	$	—	$	—	$	7.8	$	7.5	$	—	$	—	$	7.5