Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2021

Entity Information [Line Items]

Fair Value and Cost of Non-Derivative Instruments

The table below presents the fair value and cost of our non-derivative financial instruments at December 31, 2021 and 2020.

	December 31, 2021				December 31, 2020
$ in millions	Cost		Fair Value		Cost		Fair Value
Assets
Money market funds	$	0.4	$	0.4	$	0.3	$	0.3
Equity securities	1.9		5.1		2.1		4.5
Debt securities	3.8		3.9		4.0		4.1
Total assets	$	6.1	$	9.4	$	6.4	$	8.9
	Carrying Value		Fair Value		Carrying Value		Fair Value
Liabilities
Long-term debt	$	1,395.5	$	1,519.7	$	1,393.6	$	1,571.6

Fair Value of Assets and Liabilities Measured on Recurring Basis

The fair value of assets and liabilities at December 31, 2021 and 2020 and the respective category within the fair value hierarchy for DPL was determined as follows:

$ in millions	Fair Value at December 31, 2021 (a)								Fair Value at December 31, 2020 (a)
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Assets
Master trust assets
Money market funds	$	0.4	$	—	$	—	$	0.4	$	0.3	$	—	$	—	$	0.3
Equity securities	—		5.1		—		5.1		—		4.5		—		4.5
Debt securities	—		3.9		—		3.9		—		4.1		—		4.1
Total assets	$	0.4	$	9.0	$	—	$	9.4	$	0.3	$	8.6	$	—	$	8.9
Liabilities
Long-term debt	$	—	$	1,502.5	$	17.2	$	1,519.7	$	—	$	1,554.2	$	17.4	$	1,571.6
Total liabilities	$	—	$	1,502.5	$	17.2	$	1,519.7	$	—	$	1,554.2	$	17.4	$	1,571.6

(a)Includes credit valuation adjustment

THE DAYTON POWER AND LIGHT COMPANY [Member]

Entity Information [Line Items]

Fair Value and Cost of Non-Derivative Instruments

The table below presents the fair value and cost of our non-derivative instruments at December 31, 2021 and 2020. See also Note 5 – Derivative Instruments and Hedging Activities for the fair values of our derivative instruments.

	December 31, 2021				December 31, 2020
$ in millions	Cost		Fair Value		Cost		Fair Value
Assets
Money market funds	$	0.4	$	0.4	$	0.3	$	0.3
Equity securities	1.9		5.1		2.1		4.5
Debt securities	3.8		3.9		4.0		4.1
Total assets	$	6.1	$	9.4	$	6.4	$	8.9
	Carrying Value		Fair Value		Carrying Value		Fair Value
Liabilities
Long-term debt	$	574.3	$	642.6	$	574.1	$	656.0

Fair Value of Assets and Liabilities Measured on Recurring Basis

$ in millions	Fair Value at December 31, 2021 (a)								Fair Value at December 31, 2020 (a)
	Level 1		Level 2		Level 3		Total		Level 1		Level 2		Level 3		Total
Assets
Money market funds	$	0.4	$	—	$	—	$	0.4	$	0.3	$	—	$	—	$	0.3
Equity securities	—		5.1		—		5.1		—		4.5		—		4.5
Debt securities	—		3.9		—		3.9		—		4.1		—		4.1
Total assets	$	0.4	$	9.0	$	—	$	9.4	$	0.3	$	8.6	$	—	$	8.9
Liabilities
Long-term debt	$	—	$	625.4	$	17.2	$	642.6	$	—	$	638.6	$	17.4	$	656.0
Total liabilities	$	—	$	625.4	$	17.2	$	642.6	$	—	$	638.6	$	17.4	$	656.0

(a)    Includes credit valuation adjustment