Income Taxes (Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Income Taxes [Line Items]
Depreciation / property basis	$ (185.5)	$ (166.4)
Income taxes recoverable	9.2	13.6
Deferred Tax Liabilities, Regulatory Assets and Liabilities	(22.8)	(20.6)
Investment tax credit	0.1	0.6
Compensation and employee benefits	(2.8)	(3.4)
Intangibles	0.0	(0.4)
Long-term debt	5.1	(1.5)
Other	(2.3)	(9.8)
Deferred Income Tax Liabilities, Net	(199.0)	(187.9)
THE DAYTON POWER AND LIGHT COMPANY [Member]
Income Taxes [Line Items]
Depreciation / property basis	(181.3)	(167.7)
Income taxes recoverable	9.2	13.6
Deferred Tax Liabilities, Regulatory Assets and Liabilities	(22.8)	(21.4)
Investment tax credit	0.1	0.5
Compensation and employee benefits	3.1	3.4
Other	3.0	(5.0)
Deferred Income Tax Liabilities, Net	$ (194.9)	$ (183.4)

Deferred Tax Liabilities, Income Taxes Recoverable

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Deferred Tax Liabilities Long-term Debt

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[Line Items] for Income Taxes [Table]

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Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences with jurisdictional netting.

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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible tax credit carryforwards, classified as other.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from compensation and benefits costs.

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Amount of deferred tax liability attributable to taxable temporary differences from intangible assets other than goodwill.

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Amount of deferred tax liability attributable to taxable temporary differences classified as other.

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Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment.

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Amount of deferred tax liability attributable to taxable temporary differences from regulatory assets and liabilities.

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