Income Taxes (Tables)

12 Months Ended

Dec. 31, 2023

Income Taxes [Line Items]

Schedule of Unrecognized Tax Benefits Roll Forward

$ in millions	2023		2022		2021
Unrecognized tax benefits at January 1	$	0.4	$	0.4	$	1.4
Gross decreases - prior period tax positions	—		—		(1.0)
Unrecognized tax benefits at December 31	$	0.4	$	0.4	$	0.4

Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]

The amounts reclassified out of Accumulated other comprehensive loss by component during the years ended December 31, 2023, 2022 and 2021 are as follows:

Details about AOCL Components	Affected line in the Consolidated Statements of Operations	Years ended December 31,
$ in millions		2023		2022		2021
Gains and losses on cash flow hedges (Note 5):
	Interest expense, net	$	(1.0)	$	(1.0)	$	(1.0)
	Income tax effect	0.2		0.2		0.2
	Net of income taxes	(0.8)		(0.8)		(0.8)
Amortization of unfunded pension and other postretirement obligations (Note 8):
	Other expense	0.2		1.3		2.5
	Income tax effect	—		(0.3)		(0.6)
	Net of income taxes	0.2		1.0		1.9
Total reclassifications for the period, net of income taxes		$	(0.6)	$	0.2	$	1.1

Components of Income Tax Expense

DPL’s components of income tax expense for both continuing and discontinued operations were as follows:

	Years ended December 31,
$ in millions	2023		2022		2021
Components of tax expense / (benefit)
Federal - current	$	(20.0)	$	(7.6)	$	(5.5)
State and local - current	0.4		—		—
Total current	(19.6)		(7.6)		(5.5)
Federal - deferred	24.5		(2.1)		4.4
State and local - deferred	1.7		0.1		0.4
Total deferred	26.2		(2.0)		4.8
Tax expense / (benefit)	$	6.6	$	(9.6)	$	(0.7)

Schedule of Effective Income Tax Rate Reconciliation

The following table summarizes a reconciliation of the U.S. statutory federal income tax rate to the effective tax rate, as a percentage of total income before taxes:

	Years ended December 31,
	2023		2022		2021
Statutory Federal tax rate	21.0	%	21.0	%	21.0	%
State taxes, net of Federal tax benefit	2.5	%	(1.6)	%	2.8	%
AFUDC - equity	(0.2)	%	2.5	%	3.3	%
Depreciation of flow-through differences	(7.6)	%	43.8	%	(29.0)	%
Amortization of investment tax credits	—	%	0.1	%	(0.6)	%
Other, net	(0.1)	%	1.3	%	(0.8)	%
Effective tax rate	15.6	%	67.1	%	(3.3)	%

Components of Deferred Tax Assets and Liabilities

	December 31,
$ in millions	2023		2022
Net non-current assets / (liabilities)
Depreciation / property basis	$	(199.4)	$	(185.5)
Income taxes recoverable	9.5		9.2
Regulatory assets	(39.3)		(22.8)
Investment tax credit	—		0.1
Compensation and employee benefits	(3.7)		(2.8)
Long-term debt	4.9		5.1
Other (a)	0.7		(2.3)
Net non-current liabilities	$	(227.3)	$	(199.0)

(a)    The Other caption includes deferred tax assets of $35.9 million in 2023 and $36.6 million in 2022 related to state and local tax net operating loss carryforwards, with related valuation allowances of $35.7 million in 2023 and $36.6 million in 2022. These net operating loss carryforwards expire from 2024 to 2038.

Tax expense / (benefit) credited to Accumulated other comprehensive loss

The following table presents the tax expense / (benefit) related to pensions, postemployment benefits, cash flow hedges and financial instruments that were credited to Accumulated other comprehensive loss:

	Years ended December 31,
$ in millions	2023		2022		2021
Tax expense / (benefit)	$	(0.6)	$	0.8	$	2.2

THE DAYTON POWER AND LIGHT COMPANY [Member]

Income Taxes [Line Items]

Schedule of Unrecognized Tax Benefits Roll Forward

$ in millions	2023		2022		2021
Unrecognized tax benefits at January 1	$	0.4	$	0.4	$	1.4
Gross decreases - prior period tax positions	—		—		(1.0)
Unrecognized tax benefits at December 31	$	0.4	$	0.4	$	0.4

Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]

The amounts reclassified out of Accumulated other comprehensive loss by component during the years ended December 31, 2023, 2022 and 2021 are as follows:

Details about AOCL Components	Affected line in the Statements of Operations	Years ended December 31,
$ in millions		2023		2022		2021
Amortization of unfunded pension and other postretirement obligations (Note 7):
	Other expense	$	0.6	$	3.6	$	5.0
	Income tax effect	(0.2)		(0.9)		(1.1)
Total reclassifications for the period, net of income taxes		$	0.4	$	2.7	$	3.9

Components of Income Tax Expense

’s components of income tax expense were as follows:

	Years ended December 31,
$ in millions	2023		2022		2021
Components of tax expense / (benefit)
Federal - current	$	4.1	$	(0.8)	$	1.1
State and local - current	0.4		—		0.1
Total current	4.5		(0.8)		1.2
Federal - deferred	7.3		(2.4)		4.1
State and local - deferred	1.7		0.1		0.4
Total deferred	9.0		(2.3)		4.5
Tax expense / (benefit)	$	13.5	$	(3.1)	$	5.7

Schedule of Effective Income Tax Rate Reconciliation

	Years ended December 31,
	2023		2022		2021
Statutory Federal tax rate	21.0	%	21.0	%	21.0	%
State taxes, net of Federal tax benefit	1.4	%	1.4	%	1.1	%
AFUDC - Equity	(0.1)	%	(2.2)	%	1.3	%
Amortization of investment tax credits	—	%	(0.1)	%	(0.2)	%
Depreciation of flow-through differences	(4.3)	%	(39.4)	%	(11.7)	%
Change in tax reserves	—	%	—	%	(0.1)	%
Other - net	—	%	(0.3)	%	(0.6)	%
Effective tax rate	18.0	%	(19.6)	%	10.8	%

Components of Deferred Tax Assets and Liabilities

	December 31,
$ in millions	2023		2022
Net non-current assets / (liabilities)
Depreciation / property basis	$	(195.3)	$	(181.3)
Income taxes recoverable	9.5		9.2
Regulatory assets	(39.3)		(22.8)
Investment tax credit	—		0.1
Compensation and employee benefits	(4.1)		(3.1)
Operating loss carryforwards	21.0		2.4
Other	2.1		0.6
Net non-current liabilities	$	(206.1)	$	(194.9)

Tax expense / (benefit) credited to Accumulated other comprehensive loss

	Years ended December 31,
$ in millions	2023		2022		2021
Tax expense / (benefit)	$	(0.3)	$	1.5	$	2.9