DPL (DPL) 10-Q 31 Oct 24 2024 Q3 Quarterly report Financial data

Cover Statement

Cover Statement	9 Months Ended
	Sep. 30, 2024 shares
Entity Information [Line Items]
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Entity Central Index Key	0000787250
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Current Reporting Status	No
Document Type	10-Q
Document Quarterly Report	true
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity Registrant Name	DPL Inc.
Entity Incorporation, State or Country Code	OH
Entity File Number	1-9052
Entity Address, Address Line One	1065 Woodman Drive
Entity Address, Postal Zip Code	45432
Local Phone Number	259-7215
Entity Tax Identification Number	31-1163136
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding	1
Entity Address, City or Town	Dayton
Entity Address, City or Town	OH
City Area Code	937
Subsidiaries [Member]
Entity Information [Line Items]
Entity Central Index Key	0000027430
Amendment Flag	false
Entity Current Reporting Status	No
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Registrant Name	THE DAYTON POWER AND LIGHT COMPANY
Entity Incorporation, State or Country Code	OH
Entity File Number	1-2385
Entity Address, Address Line One	1065 Woodman Drive
Entity Address, Postal Zip Code	45432
Local Phone Number	259-7215
Entity Tax Identification Number	31-0258470
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding	41,172,173
Entity Address, City or Town	Dayton
Entity Address, City or Town	OH
City Area Code	937

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues	$ 227.5	$ 224.2	$ 663.1	$ 666.3
OPERATING COSTS AND EXPENSES:
Net purchased power cost	84.3	67.2	243.5	276.9
Operation and maintenance	66.9	56.6	188.9	170.7
Depreciation and amortization	25.7	20.6	69.4	60.9
Taxes other than income taxes	28.1	25.2	84.4	77.4
Loss on asset disposal	0	0	1.3	0
Costs and Expenses	205	169.6	587.5	585.9
OPERATING INCOME	22.5	54.6	75.6	80.4
OTHER INCOME / (EXPENSE), NET:
Interest expense, net	(21.1)	(7.8)	(62.2)	(45.2)
Other income, net	1.4	1.4	5.1	4.7
Total other expense, net	(19.7)	(6.4)	(57.1)	(40.5)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	2.8	48.2	18.5	39.9
Income tax expense / (benefit)	(7.5)	9.6	(4.6)	5.3
NET INCOME	10.3	38.6	23.1	34.6
Subsidiaries [Member]
Revenues	225.4	222	656.6	659.5
OPERATING COSTS AND EXPENSES:
Net purchased power cost	84.1	67.2	242.8	276.4
Operation and maintenance	66.3	56.7	187.8	169.1
Depreciation and amortization	25.2	20.3	68	59.9
Taxes other than income taxes	28.1	25.2	84.2	77.3
Loss on asset disposal	0	0	1.1	0
Costs and Expenses	203.7	169.4	583.9	582.7
OPERATING INCOME	21.7	52.6	72.7	76.8
OTHER INCOME / (EXPENSE), NET:
Interest expense, net	(11.8)	1.3	(34.7)	(16.7)
Other income, net	0.7	1.2	3.2	4
Total other expense, net	(11.1)	2.5	(31.5)	(12.7)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	10.6	55.1	41.2	64.1
Income tax expense / (benefit)	(1.9)	11.5	4.2	11.3
NET INCOME	$ 12.5	$ 43.6	$ 37	$ 52.8

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Net income	$ 10.3	$ 10.2	$ 2.6	$ 38.6	$ (5.2)	$ 1.2	$ 23.1	$ 34.6
Derivative activity:
Reclassification of earnings, net of income tax	(0.1)			(0.2)			(0.6)	(0.6)
Pension and postretirement activity:
Reclassification to earnings, net of income tax	0			0			0.1	0.1
Other comprehensive loss	(0.1)	(0.2)	(0.2)	(0.2)	(0.1)	(0.2)	(0.5)	(0.5)
NET COMPREHENSIVE INCOME	10.2			38.4			22.6	34.1
Subsidiaries [Member]
Net income	12.5			43.6	(0.4)	9.6	37	52.8
Pension and postretirement activity:
Reclassification to earnings, net of income tax	0.4			0.1			1.2	0.3
Other comprehensive loss	0.4	0.4	0.4	0.1	$ 0.1	$ 0.1	1.2	0.3
NET COMPREHENSIVE INCOME	$ 12.9			$ 43.7			$ 38.2	$ 53.1
Retained Earnings [Member] | Subsidiaries [Member]
Net income		$ 15.1	$ 9.4

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax	$ 0	$ 0	$ (0.1)	$ 0
Other Comprehensive Income (Loss), Defined Benefit Plan, Transition Asset (Obligation), Reclassification Adjustment from AOCI, after Tax	0	0	0.1	0.1
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(0.1)	(0.2)	(0.6)	(0.6)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	0.1	0	0.1	0.1
Subsidiaries [Member]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax		(0.1)	(0.4)	(0.2)
Other Comprehensive Income (Loss), Defined Benefit Plan, Transition Asset (Obligation), Reclassification Adjustment from AOCI, after Tax	$ 0.4	$ 0.1	$ 1.2	$ 0.3

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
CURRENT ASSETS:
Cash and cash equivalents	$ 41	$ 41
Accounts Receivable, after Allowance for Credit Loss, Current	101.4	92.5
Inventories	72.3	44.5
Taxes applicable to subsequent years	26.3	113
Regulatory assets, current	71.4	56.6
Income Taxes Receivable, Current	25.5	8.9
Prepayments and other current assets	14.3	6.6
Total current assets	352.2	363.1
Property, plant & equipment:
Property, plant & equipment	2,799.8	2,521.9
Less: Accumulated depreciation and amortization	(577.2)	(535.1)
Property, plant and equipment, net of depreciation	2,222.6	1,986.8
Construction work in process	269.5	234.2
Total net property, plant & equipment	2,492.1	2,221
Other non-current assets:
Regulatory assets, non-current	146.2	155.7
Intangible assets, net of amortization	162.4	114
Other non-current assets	47.6	52.4
Total other non-current assets	356.2	322.1
Total assets	3,200.5	2,906.2
Current liabilities:
Current portion of long-term debt	609	15.2
Accounts payable	123.5	163.9
Accrued taxes	114.6	101.6
Accrued interest	25.1	16.9
Contract with Customer, Liability, Current	22.1	12.7
Regulatory liabilities, current	15.8	18
Other current liabilities	35.2	22.6
Total current liabilities	945.3	350.9
Non-current liabilities:
Long-term debt	1,425.3	1,837.4
Deferred Tax Liabilities, Net	245.3	227.3
Taxes payable	0.4	113.4
Regulatory liabilities, non-current	172.2	182.1
Pension, retiree and other benefits	31.6	37.7
Other deferred credits	8.8	8.5
Total non-current liabilities	1,883.6	2,406.4
Commitments and contingencies
Common shareholder's equity:
Common stock	0	0
Other paid-in capital	3,040.5	2,840.4
Accumulated other comprehensive income	(5.1)	(4.6)
Retained Earnings (Accumulated Deficit)	(2,663.8)	(2,686.9)
Total common shareholder's equity	371.6	148.9
Total liabilities and shareholder's equity	$ 3,200.5	$ 2,906.2
Common Stock, Shares Authorized	1,500	1,500
Common stock, shares issued	1	1
Liabilities	$ 2,828.9	$ 2,757.3
Subsidiaries [Member]
CURRENT ASSETS:
Cash and cash equivalents	19.6	15.5
Accounts Receivable, after Allowance for Credit Loss, Current	101.1	93.1
Inventories	70.9	44.5
Taxes applicable to subsequent years	26.3	112.9
Regulatory assets, current	71.4	56.6
Income Taxes Receivable, Current	24.8	24.4
Prepayments and other current assets	16.1	8.1
Total current assets	330.2	355.1
Property, plant & equipment:
Property, plant & equipment	3,324.3	3,063.2
Less: Accumulated depreciation and amortization	(1,125.8)	(1,098.1)
Property, plant and equipment, net of depreciation	2,198.5	1,965.1
Construction work in process	268.4	230.8
Total net property, plant & equipment	2,466.9	2,195.9
Other non-current assets:
Regulatory assets, non-current	146.2	155.7
Intangible assets, net of amortization	160.4	111.4
Other non-current assets	46.5	52.9
Total other non-current assets	353.1	320
Total assets	3,150.2	2,871
Current liabilities:
Current portion of long-term debt	195	15.2
Accounts payable	122.4	163.8
Accrued taxes	114.5	101.4
Accrued interest	12.7	4.2
Contract with Customer, Liability, Current	22.1	12.7
Regulatory liabilities, current	15.8	18
Other current liabilities	32.2	20.2
Total current liabilities	514.7	335.5
Non-current liabilities:
Long-term debt	1,012.6	1,012.3
Deferred Tax Liabilities, Net	217.2	206.1
Taxes payable	0.4	113.4
Regulatory liabilities, non-current	172.2	182.1
Pension, retiree and other benefits	31.6	37.7
Other deferred credits	5	4.7
Total non-current liabilities	1,439	1,556.3
Commitments and contingencies
Par value common shares (in USD per share)	$ 0.01	$ 0.01
Common shareholder's equity:
Common stock	$ 0.4	$ 0.4
Other paid-in capital	1,177.5	977.4
Accumulated other comprehensive income	(26.7)	(27.9)
Retained Earnings (Accumulated Deficit)	45.3	29.3
Total common shareholder's equity	1,196.5	979.2
Total liabilities and shareholder's equity	$ 3,150.2	$ 2,871
Common Stock, Shares, Outstanding	41,172,173	41,172,173
Common Stock, Shares Authorized	50,000,000	50,000,000
Liabilities	$ 1,953.7	$ 1,891.8

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Common Stock, Shares Authorized	1,500	1,500
Common stock, shares issued	1	1
Accounts Receivable, Allowance for Credit Loss, Current	$ 1.8	$ 0.9
Cash and cash equivalents	41	41
Accounts Receivable, after Allowance for Credit Loss, Current	101.4	92.5
Inventories	72.3	44.5
Taxes applicable to subsequent years	26.3	113
Regulatory assets, current	71.4	56.6
Income Taxes Receivable, Current	25.5	8.9
Prepayments and other current assets	14.3	6.6
Property, plant & equipment	2,799.8	2,521.9
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(577.2)	(535.1)
Construction work in process	269.5	234.2
Regulatory assets, non-current	146.2	155.7
Intangible assets, net of amortization	162.4	114
Other Assets, Noncurrent	47.6	52.4
Liabilities, Current	945.3	350.9
Current portion of long-term debt	609	15.2
Accounts payable	123.5	163.9
Accrued taxes	114.6	101.6
Accrued interest	25.1	16.9
Contract with Customer, Liability, Current	22.1	12.7
Regulatory liabilities, current	15.8	18
Other current liabilities	35.2	22.6
Long-term debt	1,425.3	1,837.4
Deferred Tax Liabilities, Net	245.3	227.3
Taxes payable	0.4	113.4
Regulatory liabilities, non-current	172.2	182.1
Pension, retiree and other benefits	31.6	37.7
Other deferred credits	8.8	8.5
Common Stock, Value, Issued	0	0
Other paid-in capital	3,040.5	2,840.4
Accumulated other comprehensive income	(5.1)	(4.6)
Retained Earnings (Accumulated Deficit)	(2,663.8)	(2,686.9)
Liabilities	$ 2,828.9	$ 2,757.3
Subsidiaries [Member]
Common Stock, Shares Authorized	50,000,000	50,000,000
Common Stock, Shares, Outstanding	41,172,173	41,172,173
Common stock, par value (in USD per share)	$ 0.01	$ 0.01
Accounts Receivable, Allowance for Credit Loss, Current	$ 1.8	$ 0.9
Cash and cash equivalents	19.6	15.5
Accounts Receivable, after Allowance for Credit Loss, Current	101.1	93.1
Inventories	70.9	44.5
Taxes applicable to subsequent years	26.3	112.9
Regulatory assets, current	71.4	56.6
Income Taxes Receivable, Current	24.8	24.4
Prepayments and other current assets	16.1	8.1
Property, plant & equipment	3,324.3	3,063.2
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(1,125.8)	(1,098.1)
Construction work in process	268.4	230.8
Regulatory assets, non-current	146.2	155.7
Intangible assets, net of amortization	160.4	111.4
Other Assets, Noncurrent	46.5	52.9
Liabilities, Current	514.7	335.5
Current portion of long-term debt	195	15.2
Accounts payable	122.4	163.8
Accrued taxes	114.5	101.4
Accrued interest	12.7	4.2
Contract with Customer, Liability, Current	22.1	12.7
Regulatory liabilities, current	15.8	18
Other current liabilities	32.2	20.2
Long-term debt	1,012.6	1,012.3
Deferred Tax Liabilities, Net	217.2	206.1
Taxes payable	0.4	113.4
Regulatory liabilities, non-current	172.2	182.1
Pension, retiree and other benefits	31.6	37.7
Other deferred credits	5	4.7
Common Stock, Value, Issued	0.4	0.4
Other paid-in capital	1,177.5	977.4
Accumulated other comprehensive income	(26.7)	(27.9)
Retained Earnings (Accumulated Deficit)	45.3	29.3
Liabilities	$ 1,953.7	$ 1,891.8

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities:
Net income	$ 23.1	$ 34.6
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	69.4	60.9
Amortization of Debt Issuance Costs and Discounts	2.6	2.9
Deferred income taxes	11.6	20.9
Gain (Loss) on Disposition of Business, Including Discontinued Operation	1.3	0
Public Utilities, Allowance for Funds Used During Construction, Additions	(5.4)	(3.8)
Changes in certain assets and liabilities:
Accounts receivable, net	(8.9)	6.8
Inventories	(17.2)	(11.2)
Taxes applicable to subsequent years	86.7	69.9
Current and non-current regulatory assets and liabilities	(7.6)	(67.8)
Prepayments and other current assets	(7.6)	(5.5)
Increase (Decrease) in Other Noncurrent Assets	14.7	3.7
Accounts payable	23.8	(36.4)
Accrued taxes payable / receivable	(116.5)	(71.9)
Accrued interest	8.3	6.8
Increase (Decrease) in Other Accrued Liabilities	22	15.5
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits	(6.2)	(7.1)
Other	(0.5)	(1.4)
Net Cash Provided by (Used in) Operating Activities	93.6	16.9
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(450.7)	(286)
Payments for (Proceeds from) Removal Costs	(21.9)	(16)
Payments for (Proceeds from) Other Investing Activities	(0.8)	0.2
Net cash used in investing activities	(473.4)	(301.8)
Cash flows from financing activities:
Payments of Deferred Finance Costs	(0.2)	(0.3)
Proceeds from Lines of Credit	355	205
Repayments of Lines of Credit	(325)	(240)
Proceeds from Short-Term Debt	150	0
Proceeds from Issuance of Long-term Debt	0	100
Net cash provided by financing activities	379.8	303.7
Cash, cash equivalents, and restricted cash:
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	0	18.8
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	41.1	49.4
Non-cash financing and investing activities:
Accruals for capital expenditures	37.4	46.2
Supplemental cash flow information:
Interest paid, net of amounts capitalized	54	47.2
Proceeds from Contributions from Parent	200	239
Subsidiaries [Member]
Cash flows from operating activities:
Net income	37	52.8
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	68	59.9
Amortization of Debt Issuance Costs and Discounts	1.1	1.3
Deferred income taxes	4.2	11.3
Gain (Loss) on Disposition of Business, Including Discontinued Operation	1.1	0
Public Utilities, Allowance for Funds Used During Construction, Additions	5.4	3.8
Changes in certain assets and liabilities:
Accounts receivable, net	(8)	7.9
Inventories	(15.8)	(11.2)
Taxes applicable to subsequent years	86.6	69.8
Current and non-current regulatory assets and liabilities	(7.6)	(67.8)
Prepayments and other current assets	(8)	(7.1)
Increase (Decrease) in Other Noncurrent Assets	16.4	4.1
Accounts payable	22.7	(37.3)
Accrued taxes payable / receivable	(100.2)	(77.1)
Accrued interest	8.5	7.1
Increase (Decrease) in Other Accrued Liabilities	21.4	15.3
Increase (Decrease) in Obligation, Pension and Other Postretirement Benefits	(6.2)	(7.1)
Other	1.7	(0.3)
Net Cash Provided by (Used in) Operating Activities	117.5	17.8
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(449.6)	(283.4)
Payments for (Proceeds from) Removal Costs	(21.9)	(16)
Payments for (Proceeds from) Other Investing Activities	(0.7)	0.2
Net cash used in investing activities	(472.2)	(299.2)
Cash flows from financing activities:
Payments of Dividends	(21)	(65)
Payments of Deferred Finance Costs	(0.2)	(0.3)
Proceeds from Lines of Credit	355	205
Repayments of Lines of Credit	(325)	(205)
Proceeds from Short-Term Debt	150	0
Proceeds from Issuance of Long-term Debt	0	100
Net cash provided by financing activities	358.8	294.7
Cash, cash equivalents, and restricted cash:
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	4.1	13.3
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	19.7	33.1
Non-cash financing and investing activities:
Accruals for capital expenditures	37.4	46.2
Supplemental cash flow information:
Interest paid, net of amounts capitalized	27.2	19.2
Proceeds from Contributions from Parent	$ 200	$ 260

Statement of Shareholders' Equi

Statement of Shareholders' Equity (Statement) - USD ($) $ in Millions	Total	Subsidiaries [Member]	Common Stock [Member]	Common Stock [Member] Subsidiaries [Member]	Other Additional Capital [Member]	Other Additional Capital [Member] Subsidiaries [Member]	AOCI Attributable to Parent [Member]	AOCI Attributable to Parent [Member] Subsidiaries [Member]	Retained Earnings [Member]	Retained Earnings [Member] Subsidiaries [Member]
Shares, Issued			1	41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ (123.7)	$ 741.8	$ 0	$ 0.4	$ 2,601.3	$ 773.6	$ (2.4)	$ (26.8)	$ (2,722.6)	$ (5.4)
Other Comprehensive Income (Loss), Net of Tax	(0.2)	0.1
Net income	1.2	9.6
Stockholders' Equity, Other		0.1				0		0		(0.1)
Payments of Dividends		15				13.1				1.9
Net Income (Loss) Attributable to Parent	1.2	9.6
Other Comprehensive Income (Loss), Net of Tax	(0.5)	0.3
Net income	34.6	52.8
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	34.1	53.1
Payments of Dividends		65
Proceeds from Contributions from Parent	239	260
Shares, Issued			1	41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(122.7)	736.6	$ 0	$ 0.4	2,601.3	760.5	(2.6)	(26.7)	(2,721.4)	2.4
Other Comprehensive Income (Loss), Net of Tax	(0.1)	0.1
Net income	(5.2)	(0.4)
Stockholders' Equity, Other	(0.1)	(0.1)			(0.1)	(0.1)				0
Payments of Dividends		40				37.8				2.2
Net Income (Loss) Attributable to Parent	(5.2)	(0.4)
Proceeds from Contributions from Parent	112	125			112	125
Shares, Issued			1	41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(15.9)	821.4	$ 0	$ 0.4	2,713.4	847.8	(2.7)	(26.6)	(2,726.6)	(0.2)
Other Comprehensive Income (Loss), Net of Tax	(0.2)	0.1
Net income	38.6	43.6
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	38.4	43.7
Stockholders' Equity, Other		0.1				0				0.1
Payments of Dividends		10				5.4				4.6
Net Income (Loss) Attributable to Parent	38.6	43.6
Proceeds from Contributions from Parent		135			127	135
Shares, Issued			1	41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	149.5	990	$ 0	$ 0.4	2,840.4	977.4	(2.9)	(26.5)	(2,688)	38.7
Shares, Issued			1	41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 148.9	$ 979.2	$ 0	$ 0.4	2,840.4	977.4	(4.6)	(27.9)	(2,686.9)	29.3
Common Stock, Shares Authorized	1,500	50,000,000
Common Stock, Value, Issued	$ 0	$ 0.4
Other paid-in capital	2,840.4	977.4
Accumulated other comprehensive income	(4.6)	(27.9)
Retained Earnings (Accumulated Deficit)	(2,686.9)	$ 29.3
Par value common shares (in USD per share)		$ 0.01
Other Comprehensive Income (Loss), Net of Tax	(0.2)	$ 0.4						0.4
Net income	2.6									9.4
Stockholders' Equity, Other		0.1				0.1		0		0
Net Income (Loss) Attributable to Parent	2.6	9.4
Other Comprehensive Income (Loss), Net of Tax	(0.5)	1.2
Net income	23.1	37
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	22.6	38.2
Payments of Dividends		21
Proceeds from Contributions from Parent	200	200
Shares, Issued			1	41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	151.3	989.1	$ 0	$ 0.4	2,840.4	977.5	(4.8)	(27.5)	(2,684.3)	38.7
Other Comprehensive Income (Loss), Net of Tax	(0.2)	0.4						0.4
Net income	10.2									15.1
Payments of Dividends		21				0				21
Net Income (Loss) Attributable to Parent	10.2	15.1
Proceeds from Contributions from Parent	130	130			130
Shares, Issued			1	41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	291.3	1,113.6	$ 0	$ 0.4	2,970.4	1,107.5	(5)	(27.1)	(2,674.1)	32.8
Other Comprehensive Income (Loss), Net of Tax	(0.1)	0.4						0.4
Net income	10.3	12.5
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	10.2	12.9
Stockholders' Equity, Other					(0.1)
Net Income (Loss) Attributable to Parent	10.3	12.5
Proceeds from Contributions from Parent	70	70			70
Shares, Issued			1	41,172,173
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 371.6	$ 1,196.5	$ 0	$ 0.4	$ 3,040.5	$ 1,177.5	$ (5.1)	$ (26.7)	$ (2,663.8)	$ 45.3
Common Stock, Shares Authorized	1,500	50,000,000
Common Stock, Value, Issued	$ 0	$ 0.4
Other paid-in capital	3,040.5	1,177.5
Accumulated other comprehensive income	(5.1)	(26.7)
Retained Earnings (Accumulated Deficit)	$ (2,663.8)	$ 45.3
Par value common shares (in USD per share)		$ 0.01

Overview and Summary of Signifi

Overview and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2024
Significant Accounting Policies [Line Items]
Overview and Summary of Significant Accounting Policies	OVERVIEW AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES DPL, an indirectly wholly-owned subsidiary of AES, is a holding company organized in 1985 under the laws of Ohio. DPL owns all of the outstanding common stock of DP&L, which does business as AES Ohio. Substantially all of DPL’s business consists of transmitting, distributing and selling of electric energy conducted through its principal subsidiary, AES Ohio. The terms “we,” “us,” “our” and “ours” are used to refer to DPL and its subsidiaries. AES Ohio is a public utility incorporated in 1911 under the laws of Ohio. Beginning in 2001, Ohio law gave Ohio consumers the right to choose the electric generation supplier from whom they purchase retail generation service; however, retail transmission and distribution services are still regulated. AES Ohio has the exclusive right to provide such transmission and distribution services to approximately 541,000 customers located in West Central Ohio. Principal industries located in AES Ohio’s service territory include automotive, food processing, paper, plastic, manufacturing and defense. AES Ohio also provides retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000-square mile area of West Central Ohio. AES Ohio sources all of the generation for its SSO customers through a competitive bid process. AES Ohio's sales reflect the general economic conditions, seasonal weather patterns of the area, the market price of electricity and customer energy efficiency initiatives. AES Ohio owns numerous transmission facilities. AES Ohio records revenue and expenses for its proportional share of energy and capacity from its investment in OVEC. DPL’s other primary subsidiaries are MVIC and Miami Valley Lighting. MVIC is our captive insurance company that provides insurance services to AES Ohio and our other subsidiaries, and Miami Valley Lighting provides street and outdoor lighting services to customers in the Dayton region. DPL's subsidiaries are all wholly-owned. DPL also has a wholly-owned business trust, DPL Capital Trust II, formed for the purpose of issuing trust capital securities to investors. AES Ohio’s electric transmission and distribution businesses are subject to rate regulation by federal and state regulators. Accordingly, AES Ohio applies the accounting standards for regulated operations to its electric transmission and distribution businesses and records regulatory assets when incurred costs are expected to be recovered in future customer rates and regulatory liabilities when current cost recoveries in customer rates relate to expected future costs or overcollections of riders. Agreement to Sell Minority Interest in AES Ohio On September 13, 2024, DPL entered into (i) a Purchase and Sale Agreement with Astrid Holdings LP ("Investor"), a wholly-owned subsidiary of Caisse de dépôt et placement du Québec ("CDPQ"), pursuant to which DPL agreed to sell to Investor 15% of the issued and outstanding shares of common stock, no par value per share, of AES Ohio Holdings, Inc. ("Ohio Holdings" and, such agreement, the "Ohio Holdings Purchase Agreement") for a purchase price of approximately $273 million, subject to adjustment, and (ii) a Purchase and Sale Agreement with Investor, pursuant to which DPL agreed to sell to Investor 17.65% of the issued and outstanding shares of common stock, no par value per share, of AES Ohio Investments, Inc. ("Ohio Investments" and, such agreement, the "Ohio Investments Purchase Agreement" and together with the Ohio Holdings Purchase Agreement, the "Purchase Agreements") for a purchase price of approximately $273 million, subject to adjustment. Upon consummation of the transactions contemplated by the Ohio Holdings Purchase Agreement and the Ohio Investments Purchase Agreement together, the ("Closings"), CDPQ will own an aggregate indirect equity interest in AES Ohio of approximately 30%, with total proceeds to DPL of approximately $546 million, subject to adjustment. It is anticipated that the Closings will occur on the same day in the first half of 2025. There will be no change in management or operational control of DPL, Ohio Investments, Ohio Holdings or AES Ohio as a result of these transactions. The purchases and sales of the shares of capital stock of each of Ohio Holdings and Ohio Investments contemplated under each of the Purchase Agreements are subject to the satisfaction of certain customary conditions described in the Purchase Agreements, including, among others, receipt of the approval of the Public Utilities Commission of Ohio, the Federal Energy Regulatory Commission and completion of review by the Committee on Foreign Investments in the United States. In addition, each of the parties to the Purchase Agreements has agreed to customary covenants therein. In connection with the Closings, Investor, Ohio Investments and DPL will enter into a Shareholders' Agreement with respect to Ohio Investments (the "Shareholders' Agreement"), the form of which has been agreed to by the parties. The Shareholders' Agreement will establish the general framework governing the relationship between and among Investor and the Company, and their respective successors and transferees, as shareholders of Ohio Investments. In addition, Investor, Ohio Holdings and Ohio Investments will also enter into a Shareholders' Agreement with respect to Ohio Holdings with substantially identical terms. Consolidation DPL’s Condensed Consolidated Financial Statements include the accounts of DPL and its wholly-owned subsidiaries except for DPL Capital Trust II, which is not consolidated consistent with the provisions of GAAP. All material intercompany accounts and transactions are eliminated in consolidation. We have evaluated subsequent events through the date this report was issued. Interim Financial Presentation The accompanying unaudited condensed consolidated financial statements and footnotes have been prepared in accordance with GAAP, as contained in the FASC, for interim financial information and Article 10 of Regulation S-X issued by the SEC. Accordingly, they do not include all the information and footnotes required by GAAP for annual fiscal reporting periods. In the opinion of management, the interim financial information includes all adjustments of a normal recurring nature necessary for a fair presentation of the results of operations, financial position, comprehensive income or loss, changes in shareholder's equity, and cash flows. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of expected results for the year ending December 31, 2024. The accompanying condensed consolidated financial statements are unaudited and should be read in conjunction with the 2023 audited consolidated financial statements and footnotes thereto, which are included in our Form 10-K. Use of Management Estimates The preparation of consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities and the revenue and expenses of the periods reported. Actual results could differ from these estimates and assumptions. Significant items subject to such estimates and assumptions include: the carrying value of property, plant and equipment; unbilled revenue; the valuation of allowances for credit losses and deferred income taxes; regulatory assets and liabilities; reserves recorded for income tax exposures; litigation; contingencies; and assets and liabilities related to employee benefits. Reclassifications Certain amounts from prior periods have been reclassified to conform to the current period presentation. Cash, Cash Equivalents and Restricted Cash The following table summarizes cash, cash equivalents, and restricted cash amounts reported on the Condensed Consolidated Balance Sheets that reconcile to the total of such amounts as shown on the Condensed Consolidated Statements of Cash Flows: $ in millions September 30, 2024 December 31, 2023 Cash and cash equivalents $ 41.0 $ 41.0 Restricted cash (included in Prepayments and other current assets ) 0.1 0.1 Total cash, cash equivalents and restricted cash $ 41.1 $ 41.1 Accounts Receivable and Allowance for Credit Losses The following table summarizes accounts receivable as of September 30, 2024 and December 31, 2023: $ in millions September 30, 2024 December 31, 2023 Accounts receivable, net: Customer receivables $ 75.5 $ 71.0 Unbilled revenue 18.8 19.4 Amounts due from affiliates 2.2 0.8 Other 6.7 2.2 Allowance for credit losses (1.8) (0.9) Total accounts receivable, net $ 101.4 $ 92.5 The following table is a roll forward of our allowance for credit losses related to the accounts receivable balances for the nine months ended September 30, 2024 and 2023: Nine months ended September 30, $ in millions 2024 2023 Allowance for credit losses: Beginning balance $ 0.9 $ 0.5 Current period provision 3.8 4.1 Write-offs charged against allowance (3.5) (4.4) Recoveries collected 0.6 0.8 Ending balance $ 1.8 $ 1.0 Inventories Inventories consist of materials and supplies as of September 30, 2024 and December 31, 2023. AFUDC AES Ohio capitalizes an allowance for the net cost of funds (interest on borrowed funds and a reasonable rate of return on equity funds) used for construction purposes during the period of construction with a corresponding credit to income. During the three and nine months ended September 30, 2024 and 2023, AFUDC equity and AFUDC debt were as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 AFUDC equity $ 1.4 $ 1.3 $ 5.4 $ 3.8 AFUDC debt $ 1.8 $ 1.6 $ 6.3 $ 4.5 AOCL The changes in the components of AOCL during the nine months ended September 30, 2024 are as follows: $ in millions Change in cash flow hedges Change in unfunded pension and other postretirement obligations Total Balance as of January 1, 2024 $ 11.2 $ (15.8) $ (4.6) Amounts reclassified from AOCL to earnings (0.6) 0.1 (0.5) Balance as of September 30, 2024 $ 10.6 $ (15.7) $ (5.1) Accounting for Taxes Collected from Customers and Remitted to Governmental Authorities AES Ohio collects certain excise taxes levied by state or local governments from its customers. These taxes are accounted for on a net basis and not included in revenue. The amounts of such taxes collected for the three and nine months ended September 30, 2024 and 2023 were as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Excise taxes collected $ 13.2 $ 12.8 $ 37.2 $ 35.4 New Accounting Pronouncements Issued But Not Yet Effective The following table provides a brief description of recent accounting pronouncements that could have an impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our consolidated financial statements.
Reclassifications	Reclassifications Certain amounts from prior periods have been reclassified to conform to the current period presentation.
Subsidiaries [Member]
Significant Accounting Policies [Line Items]
Overview and Summary of Significant Accounting Policies	OVERVIEW AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES DP&L, which does business as AES Ohio, is a public utility incorporated in 1911 under the laws of Ohio. Beginning in 2001, Ohio law gave Ohio consumers the right to choose the electric generation supplier from whom they purchase retail generation service; however, retail transmission and distribution services are still regulated. AES Ohio has the exclusive right to provide such transmission and distribution services to approximately 541,000 customers located in West Central Ohio. Principal industries located in AES Ohio’s service territory include automotive, food processing, paper, plastic, manufacturing and defense. AES Ohio also provides retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000-square mile area of West Central Ohio. AES Ohio sources all of the generation for its SSO customers through a competitive bid process. AES Ohio's sales reflect the general economic conditions, seasonal weather patterns of the area, the market price of electricity and customer energy efficiency initiatives. AES Ohio owns numerous transmission facilities. AES Ohio records revenue and expenses for its proportional share of energy and capacity from its investment in OVEC. AES Ohio has one reportable segment, the Utility segment. In addition to AES Ohio's electric transmission and distribution businesses, the Utility segment includes revenue and expenses associated with AES Ohio's investment in OVEC. AES Ohio is a subsidiary of DPL. The terms “we,” “us,” “our” and “ours” are used to refer to AES Ohio. AES Ohio’s electric transmission and distribution businesses are subject to rate regulation by federal and state regulators. Accordingly, AES Ohio applies the accounting standards for regulated operations to its electric transmission and distribution businesses and records regulatory assets when incurred costs are expected to be recovered in future customer rates and regulatory liabilities when current cost recoveries in customer rates relate to expected future costs or overcollections of riders. Agreement to Sell Minority Interest in AES Ohio On September 13, 2024, DPL entered into (i) a Purchase and Sale Agreement with Astrid Holdings LP ("Investor"), a wholly-owned subsidiary of Caisse de dépôt et placement du Québec ("CDPQ"), pursuant to which DPL agreed to sell to Investor 15% of the issued and outstanding shares of common stock, no par value per share, of AES Ohio Holdings, Inc. ("Ohio Holdings" and, such agreement, the "Ohio Holdings Purchase Agreement") for a purchase price of approximately $273 million, subject to adjustment, and (ii) a Purchase and Sale Agreement with Investor, pursuant to which DPL agreed to sell to Investor 17.65% of the issued and outstanding shares of common stock, no par value per share, of AES Ohio Investments, Inc. ("Ohio Investments" and, such agreement, the "Ohio Investments Purchase Agreement" and together with the Ohio Holdings Purchase Agreement, the "Purchase Agreements") for a purchase price of approximately $273 million, subject to adjustment. Upon consummation of the transactions contemplated by the Ohio Holdings Purchase Agreement and the Ohio Investments Purchase Agreement together, the ("Closings"), CDPQ will own an aggregate indirect equity interest in AES Ohio of approximately 30%, with total proceeds to DPL of approximately $546 million, subject to adjustment. It is anticipated that the Closings will occur on the same day in the first half of 2025. There will be no change in management or operational control of DPL, Ohio Investments, Ohio Holdings or AES Ohio as a result of these transactions. The purchases and sales of the shares of capital stock of each of Ohio Holdings and Ohio Investments contemplated under each of the Purchase Agreements are subject to the satisfaction of certain customary conditions described in the Purchase Agreements, including, among others, receipt of the approval of the Public Utilities Commission of Ohio, the Federal Energy Regulatory Commission and completion of review by the Committee on Foreign Investments in the United States. In addition, each of the parties to the Purchase Agreements has agreed to customary covenants therein. In connection with the Closings, Investor, Ohio Investments and DPL will enter into a Shareholders' Agreement with respect to Ohio Investments (the "Shareholders' Agreement"), the form of which has been agreed to by the parties. The Shareholders' Agreement will establish the general framework governing the relationship between and among Investor and the Company, and their respective successors and transferees, as shareholders of Ohio Investments. In addition, Investor, Ohio Holdings and Ohio Investments will also enter into a Shareholders' Agreement with respect to Ohio Holdings with substantially identical terms. Financial Statement Presentation AES Ohio does not have any subsidiaries. We have evaluated subsequent events through the date this report was issued. Interim Financial Presentation The accompanying unaudited condensed financial statements and footnotes have been prepared in accordance with GAAP, as contained in the FASC, for interim financial information and Article 10 of Regulation S-X issued by the SEC. Accordingly, they do not include all the information and footnotes required by GAAP for annual fiscal reporting periods. In the opinion of management, the interim financial information includes all adjustments of a normal recurring nature necessary for a fair presentation of the results of operations, financial position, comprehensive income or loss, changes in shareholder's equity, and cash flows. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of expected results for the year ending December 31, 2024. The accompanying condensed financial statements are unaudited and should be read in conjunction with the 2023 audited financial statements and footnotes thereto, which are included in our Form 10-K. Use of Management Estimates The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities and the revenue and expenses of the periods reported. Actual results could differ from these estimates and assumptions. Significant items subject to such estimates and assumptions include: the carrying value of property, plant and equipment; unbilled revenue; the valuation of allowances for credit losses and deferred income taxes; regulatory assets and liabilities; reserves recorded for income tax exposures; litigation; contingencies; and assets and liabilities related to employee benefits. Reclassifications Certain amounts from prior periods have been reclassified to conform to the current period presentation. Cash, Cash Equivalents and Restricted Cash The following table summarizes cash, cash equivalents, and restricted cash amounts reported on the Condensed Balance Sheets that reconcile to the total of such amounts as shown on the Condensed Statements of Cash Flows: $ in millions September 30, 2024 December 31, 2023 Cash and cash equivalents $ 19.6 $ 15.5 Restricted cash (included in Prepayments and other current assets ) 0.1 0.1 Total cash, cash equivalents and restricted cash $ 19.7 $ 15.6 Accounts Receivable and Allowance for Credit Losses The following table summarizes accounts receivable as of September 30, 2024 and December 31, 2023: $ in millions September 30, 2024 December 31, 2023 Accounts receivable, net: Customer receivables $ 74.6 $ 70.0 Unbilled revenue 18.8 19.4 Amounts due from affiliates 2.9 2.4 Other 6.6 2.2 Allowance for credit losses (1.8) (0.9) Total accounts receivable, net $ 101.1 $ 93.1 The following table is a roll forward of our allowance for credit losses related to the accounts receivable balances for the nine months ended September 30, 2024 and 2023: Nine months ended September 30, $ in millions 2024 2023 Allowance for credit losses: Beginning balance $ 0.9 $ 0.5 Current period provision 3.8 4.1 Write-offs charged against allowance (3.5) (4.4) Recoveries collected 0.6 0.8 Ending balance $ 1.8 $ 1.0 Inventories Inventories consist of materials and supplies as of September 30, 2024 and December 31, 2023. AFUDC AES Ohio capitalizes an allowance for the net cost of funds (interest on borrowed funds and a reasonable rate of return on equity funds) used for construction purposes during the period of construction with a corresponding credit to income. During the three and nine months ended September 30, 2024 and 2023, AFUDC equity and AFUDC debt were as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 AFUDC equity $ 1.4 $ 1.3 $ 5.4 $ 3.8 AFUDC debt $ 1.8 $ 1.6 $ 6.3 $ 4.5 AOCL The changes in the components of AOCL during the nine months ended September 30, 2024 are as follows: $ in millions Change in Accumulated other comprehensive loss Balance as of January 1, 2024 $ (27.9) Amounts reclassified from AOCL to earnings 1.2 Balance as of September 30, 2024 $ (26.7) Accounting for Taxes Collected from Customers and Remitted to Governmental Authorities AES Ohio collects certain excise taxes levied by state or local governments from its customers. These taxes are accounted for on a net basis and not included in revenue. The amounts of such taxes collected for the three and nine months ended September 30, 2024 and 2023 were as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Excise taxes collected $ 13.2 $ 12.8 $ 37.2 $ 35.4 New Accounting Pronouncements Issued But Not Yet Effective The following table provides a brief description of recent accounting pronouncements that could have an impact on our financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our consolidated financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2023-07 Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures The amendments in this section are designed to improve the disclosures related to segment reporting on an interim and annual basis. Public companies must disclose significant segment expenses and an amount for other segment items. This will also require that a company disclose its annual disclosures under Topic 280 in each interim period. Furthermore, companies will need to disclose the Chief Operating Decision Maker (“CODM”) and how the CODM assesses the performance of a segment. Lastly, public companies that have a single reportable segment must report the required disclosures under Topic 280. The amendments in this Update are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. This ASU only affects disclosures, which will be provided when the amendment becomes effective. 2023-09 Income Taxes (Topic 740): Improvements to Income Tax Disclosures The amendments in this Update require that public business entities on an annual basis (1) disclose specific categories in the rate reconciliation and (2) provide additional information for reconciling items that meet a quantitative threshold. Furthermore, companies are required to disclose a disaggregated amount of income taxes paid at a federal, state, and foreign level as well as a breakdown of income taxes paid in a jurisdiction that comprises 5% of a company's total income taxes paid. Lastly, this ASU requires that companies disclose income (loss) from continuing operations before income tax at a domestic and foreign level and that companies disclose income tax expense from continuing operations on a federal, state, and foreign level. The amendments in this Update are effective for fiscal years beginning after December 15, 2024. This ASU only affects disclosures, which will be provided when the amendment becomes effective.
Reclassifications	Reclassifications Certain amounts from prior periods have been reclassified to conform to the current period presentation.

Regulatory Matters (Notes)

Regulatory Matters (Notes)	9 Months Ended
	Sep. 30, 2024
Schedule of Regulatory Assets and Liabilities [Text Block]	REGULATORY MATTERS Smart Grid Phase 2 Plan
Subsidiaries [Member]
Schedule of Regulatory Assets and Liabilities [Text Block]	REGULATORY MATTERS Smart Grid Phase 2 Plan In February 2024, AES Ohio filed a Smart Grid Phase 2 with the PUCO proposing to invest approximately $683 million in capital projects over a 10-year period following Smart Grid Phase 1, which ends June 2025. On September 13, 2024, AES Ohio reached a settlement with the PUCO Staff and other parties on the pending Smart Grid Phase 2 Application. The Settlement will provide for a four-year plan to invest $240.5 million of capital and $18.6 million of operations and maintenance expense related to grid modernization, support of Distributed Energy Resources and Economic Development and an enhanced Telecommunications network. These costs will be recovered through the existing Investment Infrastructure Rider. If approved, AES Ohio will implement a comprehensive grid modernization project that will deliver benefits to customers, society as a whole and to AES Ohio. An evidentiary hearing was held on October 29, 2024, and we expect an order from the PUCO by the second quarter of 2025, prior to the end of Smart Grid Phase 1.

Fair Value

Fair Value	9 Months Ended
	Sep. 30, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	FAIR VALUE The fair value of our financial assets and liabilities approximates their reported carrying amounts. The estimated fair values of our assets and liabilities have been determined using available market information. Because these amounts are estimates and based on hypothetical transactions to sell assets or transfer liabilities, the use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts. For further information on our valuation techniques and policies, see Note 4. Fair Value in Item 8. Financial Statements and Supplementary Data of our Form 10-K. Financial Assets AES Ohio established a Master Trust to hold assets that could be used for the benefit of employees participating in employee benefit plans. These assets are not used for general operating purposes. These assets are primarily comprised of open-ended mutual funds, which are valued using the net asset value per unit. These assets are recorded at fair value within Other non-current assets on the Condensed Consolidated Balance Sheets and are classified as equity investments. Net unrealized gains / (losses) related to equity investments still held as of September 30, 2024 and 2023 are as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Net unrealized gains / (losses) (a) $ 0.4 $ (0.2) $ 0.7 $ 0.2 (a) These amounts are included in Other income, net in our Condensed Consolidated Statements of Operations. We did not have any transfers of the fair values of our financial instruments between Level 1, Level 2 or Level 3 of the fair value hierarchy during the nine months ended September 30, 2024 or 2023. Recurring Fair Value Measurements The fair value of assets and liabilities as of September 30, 2024 and December 31, 2023 measured on a recurring basis and the respective category within the fair value hierarchy for DPL is as follows: Fair value as of September 30, 2024 Fair value as of December 31, 2023 $ in millions Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Master Trust assets Money market funds $ 0.3 $ — $ — $ 0.3 $ 0.6 $ — $ — $ 0.6 Mutual funds 7.8 — — 7.8 7.2 — — 7.2 Total assets $ 8.1 $ — $ — $ 8.1 $ 7.8 $ — $ — $ 7.8 Financial Instruments not Measured at Fair Value in the Condensed Consolidated Balance Sheets The fair value of long-term debt is based on current public market prices for disclosure purposes only. These fair value inputs are considered Level 2 in the fair value hierarchy. As the Wright-Patterson Air Force Base note is not publicly traded, the fair value inputs are considered Level 3 in the fair value hierarchy as there are no observable inputs. Unrealized gains or losses are not recognized in the financial statements as long-term debt is presented at carrying value, net of unamortized premium or discount and unamortized deferred financing costs. The long-term debt amounts include the current portion payable in the next twelve months and have maturities that range from 2025 to 2061. 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 Condensed Consolidated Balance Sheets as of the periods indicated, but for which fair value is disclosed: September 30, 2024 December 31, 2023 Carrying Amount Fair Value Carrying Amount Fair Value $ in millions Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Liabilities Long-term debt $ 1,839.3 $ — $ 1,725.2 $ 16.7 $ 1,741.9 $ 1,837.6 $ — $ 1,706.2 $ 16.8 $ 1,723.0
Subsidiaries [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	FAIR VALUE The fair value of our financial assets and liabilities approximates their reported carrying amounts. The estimated fair values of our assets and liabilities have been determined using available market information. Because these amounts are estimates and based on hypothetical transactions to sell assets or transfer liabilities, the use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts. For further information on our valuation techniques and policies, see Note 4. Fair Value in Item 8. – Financial Statements and Supplementary Data of our Form 10-K. Financial Assets AES Ohio established a Master Trust to hold assets that could be used for the benefit of employees participating in employee benefit plans. These assets are not used for general operating purposes. These assets are primarily comprised of open-ended mutual funds, which are valued using the net asset value per unit. These assets are recorded at fair value within Other non-current assets on the Condensed Balance Sheets and are classified as equity investments. Net unrealized gains / (losses) related to equity investments still held as of September 30, 2024 and 2023 are as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Net unrealized gains (a) $ 0.4 $ (0.2) $ 0.7 $ 0.2 (a) These amounts are included in Other income, net in our Condensed Statements of Operations. We did not have any transfers of the fair values of our financial instruments between Level 1, Level 2 or Level 3 of the fair value hierarchy during the nine months ended September 30, 2024 or 2023. Recurring Fair Value Measurements The fair value of assets and liabilities as of September 30, 2024 and December 31, 2023 measured on a recurring basis and the respective category within the fair value hierarchy for AES Ohio is as follows: Fair value as of September 30, 2024 Fair value as of December 31, 2023 $ in millions Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Master Trust assets Money market funds $ 0.3 $ — $ — $ 0.3 $ 0.6 $ — $ — $ 0.6 Mutual funds 7.8 — — 7.8 7.2 — — 7.2 Total assets $ 8.1 $ — $ — $ 8.1 $ 7.8 $ — $ — $ 7.8 Financial Instruments not Measured at Fair Value in the Condensed Balance Sheets The fair value of long-term debt is based on current public market prices for disclosure purposes only. These fair value inputs are considered Level 2 in the fair value hierarchy. As the Wright-Patterson Air Force Base note is not publicly traded, the fair value inputs are considered Level 3 in the fair value hierarchy as there are no observable inputs. Unrealized gains or losses are not recognized in the financial statements as long-term debt is presented at carrying value, net of unamortized premium or discount and unamortized deferred financing costs. The long-term debt amounts include the current portion payable in the next twelve months and have maturities that range from 2027 to 2061. 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 Condensed Balance Sheets as of the periods indicated, but for which fair value is disclosed: September 30, 2024 December 31, 2023 Carrying Amount Fair Value Carrying Amount Fair Value $ in millions Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Liabilities Long-term debt $ 1,012.8 $ — $ 918.8 $ 16.7 $ 935.5 $ 1,012.5 $ — $ 909.9 $ 16.8 $ 926.7

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Instruments and Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES For further information on our derivative and hedge accounting policies, see Note 1. Overview and Summary of Significant Accounting Policies – Financial Derivatives and Note 5. Derivative Instruments and Hedging Activities of Item 8. Financial Statements and Supplementary Data in our Form 10-K. Cash Flow Hedges DPL previously used derivative financial instruments primarily to manage the interest rate risk associated with our long-term debt. These interest rate derivative contracts were settled in 2013, and we continue to amortize amounts out of AOCL into interest expense. The following tables provide information concerning gains recognized in AOCL for the cash flow hedges for the three and nine months ended September 30, 2024 and 2023: Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Interest Interest Interest Interest $ in millions (net of tax) Rate Hedge Rate Hedge Rate Hedge Rate Hedge Beginning accumulated derivative gains in AOCL $ 10.7 $ 11.6 $ 11.2 $ 12.0 Net gains reclassified to earnings Interest expense (0.1) (0.2) (0.6) (0.6) Ending accumulated derivative gains in AOCL $ 10.6 $ 11.4 $ 10.6 $ 11.4 Portion expected to be reclassified to earnings in the next twelve months $ (0.8)

Debt Obligations

Debt Obligations	9 Months Ended
	Sep. 30, 2024
Debt Instrument [Line Items]
Long-term Debt	DEBT Long-term debt is as follows: Interest September 30, December 31, $ in millions Rate Due 2024 2023 AES Ohio debt First Mortgage Bonds 3.95 % 2049 $ 425.0 $ 425.0 First Mortgage Bonds 3.20 % 2040 140.0 140.0 First Mortgage Bonds 5.70 % 2033 107.5 107.5 First Mortgage Bonds 5.19 % 2033 100.0 100.0 First Mortgage Bonds 5.49 % 2028 92.5 92.5 Tax-exempt First Mortgage Bonds (a) 4.25 % 2027 100.0 100.0 Tax-exempt First Mortgage Bonds (b) 4.00 % 2027 40.0 40.0 U.S. Government note 4.20 % 2061 16.7 16.8 Unamortized deferred financing costs (6.6) (7.1) Unamortized debt discounts (2.3) (2.2) Total long-term debt at AES Ohio 1,012.8 1,012.5 DPL Inc. debt Senior unsecured notes 4.125 % 2025 415.0 415.0 Senior unsecured notes 4.35 % 2029 400.0 400.0 Note to DPL Capital Trust II (c) 8.125 % 2031 15.6 15.6 Unamortized deferred financing costs (3.5) (4.9) Unamortized debt discounts (0.6) (0.6) Total DPL consolidated long-term debt 1,839.3 1,837.6 Less: current portion (414.0) (0.2) DPL consolidated long-term debt, net of current portion $ 1,425.3 $ 1,837.4 (a) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of November 1, 2040 but are subject to a mandatory put in June 2027. (b) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of January 1, 2034 but are subject to a mandatory put in June 2027. (c) Note payable to related party. Revolving credit agreements As of September 30, 2024 and December 31, 2023, the AES Ohio Credit Agreement had outstanding borrowings of $45.0 million and $15.0 million, respectively. Significant Transactions In August 2024, AES Ohio entered into an unsecured $150.0 million 364-day term loan agreement ("AES Ohio Term Loan"). The AES Ohio Term Loan was fully drawn at closing with the proceeds being used for general corporate purposes. This agreement matures on August 13, 2025, and bears interest at variable rates as described in the $150 million Term Loan Agreement. The AES Ohio Term Loan contains customary representations, warranties and covenants, including a leverage covenant consistent with the leverage covenant contained in AES Ohio's Credit Agreement. AES Ohio has classified the AES Ohio Term Loan as short-term indebtedness as it matures in August 2025. Management plans to repay the AES Ohio Term Loan Agreement through a combination of funds from debt financings and parent equity capital contributions. DPL's Senior unsecured notes DPL has $415.0 million of 4.125% Senior unsecured notes due July 1, 2025 ("2025 DPL Notes"). Although current liquid funds are not sufficient to repay the amounts due under the 2025 DPL Notes at maturity, we will use a portion of the proceeds from the Closings to repay the notes in full (see Note 1. Overview and Summary of Significant Accounting Policies - Agreement to Sell Minority Interest in AES Ohio for more information). Long-term debt covenants and restrictions The AES Ohio Credit Agreement, AES Ohio Term Loan, and Fifty-Third, Fifty-Fourth and Fifty-Fifth Supplemental Indentures to the First Mortgage, pursuant to which the 3.20% Bonds due 2040, the 5.19% Bonds due 2033, the 5.49% Bonds due 2028 and the 5.70% Bonds due 2033 were issued, respectively, each contain one financial covenant. The covenant measures Total Debt to Total Capitalization and is calculated, at the end of each fiscal quarter, by dividing total debt at the end of the quarter by total capitalization at the end of the quarter. AES Ohio’s Total Debt to Total Capitalization ratio shall not be greater than 0.67 to 1.00. As of September 30, 2024, AES Ohio was in compliance with this financial covenant. AES Ohio does not have any meaningful restrictions in its debt financing documents prohibiting dividends and return of capital payments to its parent, DPL. As of September 30, 2024, AES Ohio was in compliance with all debt covenants, including the financial covenant described above. Substantially all property, plant & equipment of AES Ohio is subject to the lien of the mortgage securing AES Ohio’s First and Refunding Mortgage.
Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term Debt	DEBT Long-term debt is as follows: Interest September 30, December 31, $ in millions Rate Due 2024 2023 First Mortgage Bonds 3.95 % 2049 $ 425.0 $ 425.0 First Mortgage Bonds 3.20 % 2040 140.0 140.0 First Mortgage Bonds 5.70 % 2033 107.5 107.5 First Mortgage Bonds 5.19 % 2033 100.0 100.0 First Mortgage Bonds 5.49 % 2028 92.5 92.5 Tax-exempt First Mortgage Bonds (a) 4.25 % 2027 100.0 100.0 Tax-exempt First Mortgage Bonds (b) 4.00 % 2027 40.0 40.0 U.S. Government note 4.20 % 2061 16.7 16.8 Unamortized deferred financing costs (6.6) (7.1) Unamortized debt discounts (2.3) (2.2) Total long-term debt 1,012.8 1,012.5 Less: current portion (0.2) (0.2) Long-term debt, net of current portion $ 1,012.6 $ 1,012.3 (a) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of November 1, 2040 but are subject to a mandatory put in June 2027. (b) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of January 1, 2034 but are subject to a mandatory put in June 2027. Revolving credit agreements As of September 30, 2024 and December 31, 2023, the AES Ohio Credit Agreement had outstanding borrowings of $45.0 million and $15.0 million, respectively. Significant Transactions In August 2024, AES Ohio entered into an unsecured $150.0 million 364-day term loan agreement ("AES Ohio Term Loan"). The AES Ohio Term Loan was fully drawn at closing with the proceeds being used for general corporate purposes. This agreement matures on August 13, 2025, and bears interest at variable rates as described in the $150 million Term Loan Agreement. The AES Ohio Term Loan contains customary representations, warranties and covenants, including a leverage covenant consistent with the leverage covenant contained in AES Ohio's Credit Agreement. AES Ohio has classified the AES Ohio Term Loan as short-term indebtedness as it matures in August 2025. Management plans to repay the AES Ohio Term Loan Agreement through a combination of funds from debt financings and parent equity capital contributions. Long-term debt covenants and restrictions The AES Ohio Credit Agreement, AES Ohio Term Loan, and Fifty-Third, Fifty-Fourth and Fifty-Fifth Supplemental Indentures to the First Mortgage, pursuant to which the 3.20% Bonds due 2040, the 5.19% Bonds due 2033, the 5.49% Bonds due 2028 and the 5.70% Bonds due 2033 were issued, respectively, each contain one financial covenant. The covenant measures Total Debt to Total Capitalization and is calculated, at the end of each fiscal quarter, by dividing total debt at the end of the quarter by total capitalization at the end of the quarter. AES Ohio’s Total Debt to Total Capitalization ratio shall not be greater than 0.67 to 1.00. As of September 30, 2024, AES Ohio was in compliance with this financial covenant. As of September 30, 2024, AES Ohio was in compliance with all debt covenants, including the financial covenant described above. AES Ohio does not have any meaningful restrictions in its debt financing documents prohibiting dividends and return of capital payments to its parent, DPL. Substantially all property, plant & equipment of AES Ohio is subject to the lien of the mortgage securing AES Ohio’s First and Refunding Mortgage.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2024
Entity Information [Line Items]
Income Taxes	INCOME TAXES DPL’s provision for income taxes is based on the estimated annual effective tax rate, plus discrete items. The effective combined state and federal income tax rates were as follows: Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Effective tax rate (267.9) % 19.9 % (24.9) % 13.3 % The year-to-date rate is different from the combined federal and state statutory rate of 22.4% primarily due to the flowthrough of the net tax benefit related to the reversal of excess deferred taxes of AES Ohio as a percentage of pre-tax book income or loss. AES Ohio began amortizing a deferred municipal tax shortage in September 2023, which partially offsets the ongoing amortization of the TCJA benefit. DPL's income tax expense for the nine months ended September 30, 2024 was calculated using the estimated annual effective income tax rate for 2024 of (53.1)% on ordinary income. Management estimates the annual effective tax rate based on its forecast of annual pre-tax income or loss. DPL's current period tax benefit was calculated using the limitations prescribed in ASC 740-270-30-30 through 740-270-30-33. AES files federal and state income tax returns, which consolidate DPL and its subsidiaries. Under a tax sharing agreement with AES, DPL is responsible for the income taxes associated with its own taxable income and records the provision for income taxes using a separate return method.
Subsidiaries [Member]
Entity Information [Line Items]
Income Taxes	INCOME TAXES AES Ohio's provision for income taxes is based on the estimated annual effective tax rate, plus discrete items. The effective combined state and federal income tax rates were as follows: Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Effective combined state and federal income tax rates (17.9) % 20.9 % 10.2 % 17.6 % The year-to-date rate is different from the combined federal and state statutory rate of 22.4% primarily due to the flowthrough of the net tax benefit related to the reversal of excess deferred taxes of AES Ohio as a percentage of pre-tax book income or loss. AES Ohio began amortizing a deferred municipal tax shortage in September 2023, which partially offsets the ongoing amortization of the TCJA benefit. AES files federal and state income tax returns, which consolidate AES Ohio. Under a tax sharing agreement with DPL, AES Ohio is responsible for the income taxes associated with its own taxable income and records the provision for income taxes using a separate return method.

Benefit Plans

Benefit Plans	9 Months Ended
	Sep. 30, 2024
Pension [Member]
Entity Information [Line Items]
Pension and Postretirement Benefits	BENEFIT PLANS The amounts presented in the following tables for pension include both of the Pension Plans. The pension costs below have not been adjusted for amounts billed to the Service Company for former AES Ohio employees who are now employed by the Service Company or other AES affiliates that are still participants in the AES Ohio plans. The following table presents the net periodic benefit cost of the Pension Plans for the three and nine months ended September 30, 2024 and 2023: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Service cost $ 0.7 $ 0.8 $ 1.9 $ 2.2 Interest cost 3.6 3.9 11.0 11.9 Expected return on plan assets (3.7) (4.4) (11.1) (13.2) Amortization of unrecognized: Prior service cost 0.2 0.3 0.7 0.8 Actuarial loss 0.5 0.2 1.6 0.5 Net periodic benefit cost $ 1.3 $ 0.8 $ 4.1 $ 2.2 The components of net periodic benefit cost other than service cost are included in Other income, net in the Condensed Consolidated Statements of Operations. There were $7.5 million in employer contributions during each of the nine month periods ended September 30, 2024 and 2023. In addition, AES Ohio provides postretirement health care and life insurance benefits to certain retired employees, their spouses and eligible dependents. We have funded a portion of the union-eligible benefits using a Voluntary Employee Beneficiary Association Trust. These postretirement health care benefits and the related unfunded obligation were not material to the financial statements in the periods covered by this report.
Subsidiaries [Member]
Entity Information [Line Items]
Pension and Postretirement Benefits	BENEFIT PLANS The amounts presented in the following tables for pension include both of the Pension Plans. The pension costs below have not been adjusted for amounts billed to the Service Company for former AES Ohio employees who are now employed by the Service Company or other AES affiliates or for amounts billed to AES Ohio Generation for former employees that were employed by AES Ohio Generation that are still participants in the AES Ohio plans. The following table presents the net periodic benefit cost of the Pension Plans for the three and nine months ended September 30, 2024 and 2023: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Service cost $ 0.7 $ 0.8 $ 1.9 $ 2.2 Interest cost 3.6 3.9 11.0 11.9 Expected return on plan assets (3.7) (4.4) (11.1) (13.2) Amortization of unrecognized: Prior service cost 0.3 0.2 0.7 0.8 Actuarial loss 0.9 0.3 2.9 0.9 Net periodic benefit cost $ 1.8 $ 0.8 $ 5.4 $ 2.6 The components of net periodic benefit cost other than service cost are included in Other income, net in the Condensed Statements of Operations. There were $7.5 million in employer contributions during each of the nine month periods ended September 30, 2024 and 2023. In addition, AES Ohio provides postretirement health care and life insurance benefits to certain retired employees, their spouses and eligible dependents. We have funded a portion of the union-eligible benefits using a Voluntary Employee Beneficiary Association Trust. These postretirement health care benefits and the related unfunded obligation were not material to the financial statements in the periods covered by this report.

Equity

Equity	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Stockholders' Equity Note Disclosure	During the nine months ended September 30, 2024, DPL received $200.0 million in equity contributions from AES. DPL then made the same investment in AES Ohio.

Contractual Obligations, Commer

Contractual Obligations, Commercial Commitments and Contingencies	9 Months Ended
	Sep. 30, 2024
Entity Information [Line Items]
Contractual Obligations, Commercial Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Contingencies Legal Matters In the normal course of business, we are subject to various lawsuits, actions, proceedings, claims and other matters asserted under various laws and regulations. We believe the amounts provided in our Condensed Consolidated Financial Statements, as prescribed by GAAP, are adequate considering the probable and estimable contingencies. However, there can be no assurances that the actual amounts required to satisfy alleged liabilities from various legal proceedings, claims, tax examinations and other matters discussed below, and to comply with applicable laws and regulations, will not exceed the amounts reflected in our Condensed Consolidated Financial Statements. As such, costs, if any, that may be incurred in excess of those amounts provided as of September 30, 2024, cannot be reasonably determined. Environmental Matters We are subject to various federal, state, regional and local environmental protection and health and safety laws and regulations governing, among other things, the generation, storage, handling, use, disposal and transportation of regulated materials, including ash and CCR; the use and discharge of water used in generation boilers and for cooling purposes; the emission and discharge of hazardous and other materials, including GHGs, into the environment; climate change; species and habitat protections; and the health and safety of our employees. These laws and regulations often require a lengthy and complex process of obtaining and renewing permits and other governmental authorizations from federal, state and local agencies. Violation of these laws, regulations or permits can result in substantial fines, other sanctions, permit revocation and/or facility shutdowns. We cannot assure that we have been or will be at all times in full compliance with such laws, regulations and permits. Where no accrued liability has been recognized, it is reasonably possible that some matters could be decided unfavorably to us and could require us to pay damages or make expenditures in amounts that could be material but could not be estimated as of September 30, 2024. We have taken steps to limit our exposure to environmental claims that could be raised with respect to our previously-owned and operated coal-fired generation units, but we cannot predict whether any such claims will be raised and, if they are, the extent to which they may have a material adverse effect on our results of operations, financial condition and cash flows. Accruals for legal loss and environmental contingencies were not material as of September 30, 2024 and December 31, 2023. Equity Ownership Interest AES Ohio has a 4.9% equity ownership interest in OVEC, which is recorded using the cost method of accounting under GAAP. AES Ohio, along with several non-affiliated energy companies party to an OVEC arrangement, receive and pay for OVEC capacity and energy and are responsible for OVEC debt obligations and other fixed costs in proportion to their power participation ratios under the arrangement, which, for AES Ohio, is the same as its equity ownership interest. As of September 30, 2024, AES Ohio could be responsible for the repayment of 4.9%, or $49.7 million, of $1.0 billion OVEC debt obligations if they came due, comprised of fixed rate securities with maturities from 2026 to 2040. OVEC could also seek additional contributions from AES Ohio to avoid a default in the event that other OVEC members defaulted on their respective OVEC obligations.
Subsidiaries [Member]
Entity Information [Line Items]
Contractual Obligations, Commercial Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Contingencies Legal Matters In the normal course of business, we are subject to various lawsuits, actions, proceedings, claims and other matters asserted under various laws and regulations. We believe the amounts provided in our Condensed Financial Statements, as prescribed by GAAP, are adequate considering the probable and estimable contingencies. However, there can be no assurances that the actual amounts required to satisfy alleged liabilities from various legal proceedings, claims, tax examinations and other matters discussed below, and to comply with applicable laws and regulations, will not exceed the amounts reflected in our Condensed Financial Statements. As such, costs, if any, that may be incurred in excess of those amounts provided as of September 30, 2024, cannot be reasonably determined. Environmental Matters We are subject to various federal, state, regional and local environmental protection and health and safety laws and regulations governing, among other things, the generation, storage, handling, use, disposal and transportation of regulated materials, including ash and CCR; the use and discharge of water used in generation boilers and for cooling purposes; the emission and discharge of hazardous and other materials, including GHGs, into the environment; climate change; species and habitat protections; and the health and safety of our employees. These laws and regulations often require a lengthy and complex process of obtaining and renewing permits and other governmental authorizations from federal, state and local agencies. Violation of these laws, regulations or permits can result in substantial fines, other sanctions, permit revocation and/or facility shutdowns. We cannot assure that we have been or will be at all times in full compliance with such laws, regulations and permits. Where no accrued liability has been recognized, it is reasonably possible that some matters could be decided unfavorably to us and could require us to pay damages or make expenditures in amounts that could be material but could not be estimated as of September 30, 2024. We have taken steps to limit our exposure to environmental claims that could be raised with respect to our previously-owned and operated coal-fired generation units, but we cannot predict whether any such claims will be raised and, if they are, the extent to which they may have a material adverse effect on our results of operations, financial condition and cash flows. Accruals for legal loss and environmental contingencies were not material as of September 30, 2024 and December 31, 2023. Equity Ownership Interest AES Ohio has a 4.9% equity ownership interest in OVEC, which is recorded using the cost method of accounting under GAAP. AES Ohio, along with several non-affiliated energy companies party to an OVEC arrangement, receive and pay for OVEC capacity and energy and are responsible for OVEC debt obligations and other fixed costs in proportion to their power participation ratios under the arrangement, which, for AES Ohio, is the same as its equity ownership interest. As of September 30, 2024, AES Ohio could be responsible for the repayment of 4.9%, or $49.7 million, of $1.0 billion OVEC debt obligations if they came due, comprised of fixed rate securities with maturities from 2026 to 2040. OVEC could also seek additional contributions from AES Ohio to avoid a default in the event that other OVEC members defaulted on their respective OVEC obligations.

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2024
Segment Reporting Information [Line Items]
Business Segments	BUSINESS SEGMENTS DPL manages its business through one reportable operating segment, the Utility segment. The primary segment performance measure is income / (loss) before income tax as management has concluded that this measure best reflects the underlying business performance of DPL and is the most relevant measure considered in DPL’s internal evaluation of the financial performance of its segment. The Utility segment is comprised of AES Ohio, a public electric transmission and distribution utility, with all other nonutility business activities aggregated separately. See Note 1. Overview and Summary of Significant Accounting Policies for further information on AES Ohio. The “Other” nonutility category primarily includes interest expense, cash and other immaterial balances. The accounting policies of the identified segment are consistent with those policies and procedures described in the summary of significant accounting policies. The following tables present financial information for DPL’s reportable business segment: $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Three months ended September 30, 2024 Revenue from external customers $ 225.1 $ 2.4 $ — $ 227.5 Intersegment revenue 0.3 1.2 (1.5) — Total revenue $ 225.4 $ 3.6 $ (1.5) $ 227.5 Depreciation and amortization $ 25.2 $ 0.5 $ — $ 25.7 Interest expense, net $ 11.8 $ 9.3 $ — $ 21.1 Income / (loss) before income tax $ 10.6 $ (7.8) $ — $ 2.8 $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Three Months Ended September 30, 2023 Revenue from external customers $ 221.8 $ 2.4 $ — $ 224.2 Intersegment revenue 0.2 1.5 (1.7) — Total revenue $ 222.0 $ 3.9 $ (1.7) $ 224.2 Depreciation and amortization $ 20.3 $ 0.3 $ — $ 20.6 Interest expense, net $ (1.3) $ 9.1 $ — $ 7.8 Income / (loss) before income tax $ 55.1 $ (6.9) $ — $ 48.2 $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Nine months ended September 30, 2024 Revenue from external customers $ 655.9 $ 7.2 $ — $ 663.1 Intersegment revenue 0.7 3.7 (4.4) — Total revenue $ 656.6 $ 10.9 $ (4.4) $ 663.1 Depreciation and amortization $ 68.0 $ 1.4 $ — $ 69.4 Interest expense, net $ 34.7 $ 27.5 $ — $ 62.2 Income / (loss) before income tax $ 41.2 $ (22.7) $ — $ 18.5 $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Nine months ended September 30, 2023 Revenue from external customers $ 659.0 $ 7.3 $ — $ 666.3 Intersegment revenue 0.5 3.2 (3.7) — Total revenue $ 659.5 $ 10.5 $ (3.7) $ 666.3 Depreciation and amortization $ 59.9 $ 1.0 $ — $ 60.9 Interest expense, net $ 16.7 $ 28.5 $ — $ 45.2 Income / (loss) before income tax $ 64.1 $ (24.2) $ — $ 39.9 Total Assets ($ in millions) September 30, 2024 December 31, 2023 Utility $ 3,150.2 $ 2,871.0 All Other (a) 50.3 35.2 DPL Consolidated $ 3,200.5 $ 2,906.2 (a)

Revenue (Notes)

Revenue (Notes)	9 Months Ended
	Sep. 30, 2024
Revenue from Contract with Customer [Text Block]	REVENUE Revenue is primarily earned from retail and wholesale electricity sales and electricity transmission and distribution delivery services. Revenue is recognized upon transfer of control to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. Revenue is recorded net of any taxes assessed on and collected from customers, which are remitted to the governmental authorities. For further discussion of our Retail, Wholesale, RTO ancillary, and Capacity revenue, see Note 13. Revenue in Item 8. Financial Statements and Supplementary Data of our Form 10-K. DPL's revenue from contracts with customers was as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Revenue from contracts with customers $ 224.3 $ 225.8 $ 654.7 $ 668.7 The following table presents our revenue from contracts with customers and other revenue by segment for the three and nine months ended September 30, 2024 and 2023: $ in millions Utility Other Adjustments and Eliminations Total Three Months Ended September 30, 2024 Retail revenue Retail revenue from contracts with customers Residential revenue $ 120.9 $ — $ — $ 120.9 Commercial revenue 41.9 — — 41.9 Industrial revenue 17.4 — — 17.4 Governmental revenue 7.4 — — 7.4 Other (a) 2.7 — — 2.7 Total retail revenue from contracts with customers 190.3 — — 190.3 Wholesale revenue Wholesale revenue from contracts with customers 4.5 — (0.2) 4.3 RTO ancillary revenue 27.0 — — 27.0 Capacity revenue 0.3 — — 0.3 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 2.4 — 2.4 Other miscellaneous revenue 3.3 1.2 (1.3) 3.2 Total revenue $ 225.4 $ 3.6 $ (1.5) $ 227.5 Three Months Ended September 30, 2023 Retail revenue Retail revenue from contracts with customers Residential revenue $ 127.8 $ — $ — $ 127.8 Commercial revenue 42.7 — — 42.7 Industrial revenue 16.5 — — 16.5 Governmental revenue 6.8 — — 6.8 Other (a) 3.5 — — 3.5 Total retail revenue from contracts with customers 197.3 — — 197.3 Other retail revenue (0.2) — — (0.2) Wholesale revenue Wholesale revenue from contracts with customers 4.2 — (0.2) 4.0 RTO ancillary revenue 21.4 0.1 — 21.5 Capacity revenue 0.7 — — 0.7 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 2.3 — 2.3 Other miscellaneous revenue (1.4) 1.5 (1.5) (1.4) Total revenue $ 222.0 $ 3.9 $ (1.7) $ 224.2 $ in millions Utility Other Adjustments and Eliminations Total Nine months ended September 30, 2024 Retail revenue Retail revenue from contracts with customers Residential revenue $ 347.1 $ — $ — $ 347.1 Commercial revenue 120.5 — — 120.5 Industrial revenue 50.1 — — 50.1 Governmental revenue 19.5 — — 19.5 Other (a) 9.0 — — 9.0 Total retail revenue from contracts with customers 546.2 — — 546.2 Other retail revenue — — — — Wholesale revenue Wholesale revenue from contracts with customers 12.3 — (0.7) 11.6 RTO ancillary revenue 89.0 — — 89.0 Capacity revenue 0.7 — — 0.7 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 7.2 — 7.2 Other miscellaneous revenue 8.4 3.7 (3.7) 8.4 Total revenue $ 656.6 $ 10.9 $ (4.4) $ 663.1 Nine months ended September 30, 2023 Retail revenue Retail revenue from contracts with customers Residential revenue $ 377.9 $ — $ — $ 377.9 Commercial revenue 124.8 — — 124.8 Industrial revenue 50.4 — — 50.4 Governmental revenue 18.7 — — 18.7 Other (a) 9.9 — — 9.9 Total retail revenue from contracts with customers 581.7 — — 581.7 Other retail revenue (0.2) — — (0.2) Wholesale revenue Wholesale revenue from contracts with customers 11.3 — (0.5) 10.8 RTO ancillary revenue 65.7 0.1 — 65.8 Capacity revenue 3.2 — — 3.2 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 7.2 — 7.2 Other miscellaneous revenue (2.2) 3.2 (3.2) (2.2) Total revenue $ 659.5 $ 10.5 $ (3.7) $ 666.3 (a ) "Other" primarily includes operation and maintenance service revenue, billing service fees from CRES providers and other miscellaneous retail revenue from contracts with customers. (b) Miscellaneous revenue from contracts with customers primarily includes revenue for various services provided by Miami Valley Lighting. The balances of receivables from customers were as follows: $ in millions September 30, 2024 December 31, 2023 Receivables from contracts with customers $ 94.3 $ 90.4 Payment terms for all receivables from contracts with customers are typically within 30 days unless a customer qualifies for payment extension.
Subsidiaries [Member]
Revenue from Contract with Customer [Text Block]	REVENUE Revenue is primarily earned from retail and wholesale electricity sales and electricity transmission and distribution delivery services. Revenue is recognized upon transfer of control to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. Revenue is recorded net of any taxes assessed on and collected from customers, which are remitted to the governmental authorities. For further discussion of our Retail, Wholesale, RTO ancillary, and Capacity revenue, see Note 11. Revenue in Item 8. Financial Statements and Supplementary Data of our Form 10-K. AES Ohio's revenue from contracts with customers was as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Revenue from contracts with customers $ 222.1 $ 223.6 $ 648.2 $ 661.9 The following table presents our revenue from contracts with customers and other revenue for the three and nine months ended September 30, 2024 and 2023: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Retail revenue Retail revenue from contracts with customers Residential revenue $ 120.9 $ 127.8 $ 347.1 $ 377.9 Commercial revenue 41.9 42.7 120.5 124.8 Industrial revenue 17.4 16.5 50.1 50.4 Governmental revenue 7.4 6.8 19.5 18.7 Other (a) 2.7 3.5 9.0 9.9 Total retail revenue from contracts with customers 190.3 197.3 546.2 581.7 Other retail revenue — (0.2) — (0.2) Wholesale revenue Wholesale revenue from contracts with customers 4.5 4.2 12.3 11.3 RTO ancillary revenue 27.0 21.4 89.0 65.7 Capacity revenue 0.3 0.7 0.7 3.2 Miscellaneous revenue 3.3 (1.4) 8.4 (2.2) Total revenue $ 225.4 $ 222.0 $ 656.6 $ 659.5 (a ) "Other" primarily includes operation and maintenance service revenue, billing service fees from CRES providers and other miscellaneous retail revenue from contracts with customers. The balances of receivables from customers were as follows: $ in millions September 30, 2024 December 31, 2023 Receivables from contracts with customers $ 93.4 $ 89.4 Payment terms for all receivables from contracts with customers are typically within 30 days unless a customer qualifies for payment extension.

Summary of Significant Accounti

Summary of Significant Accounting Policies (Policy)	9 Months Ended
	Sep. 30, 2024
Significant Accounting Policies [Line Items]
Inventory, Policy	Inventories Inventories consist of materials and supplies as of September 30, 2024 and December 31, 2023.
Description of Business	DPL, an indirectly wholly-owned subsidiary of AES, is a holding company organized in 1985 under the laws of Ohio. DPL owns all of the outstanding common stock of DP&L, which does business as AES Ohio. Substantially all of DPL’s business consists of transmitting, distributing and selling of electric energy conducted through its principal subsidiary, AES Ohio. The terms “we,” “us,” “our” and “ours” are used to refer to DPL and its subsidiaries. AES Ohio is a public utility incorporated in 1911 under the laws of Ohio. Beginning in 2001, Ohio law gave Ohio consumers the right to choose the electric generation supplier from whom they purchase retail generation service; however, retail transmission and distribution services are still regulated. AES Ohio has the exclusive right to provide such transmission and distribution services to approximately 541,000 customers located in West Central Ohio. Principal industries located in AES Ohio’s service territory include automotive, food processing, paper, plastic, manufacturing and defense. AES Ohio also provides retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000-square mile area of West Central Ohio. AES Ohio sources all of the generation for its SSO customers through a competitive bid process. AES Ohio's sales reflect the general economic conditions, seasonal weather patterns of the area, the market price of electricity and customer energy efficiency initiatives. AES Ohio owns numerous transmission facilities. AES Ohio records revenue and expenses for its proportional share of energy and capacity from its investment in OVEC. DPL’s other primary subsidiaries are MVIC and Miami Valley Lighting. MVIC is our captive insurance company that provides insurance services to AES Ohio and our other subsidiaries, and Miami Valley Lighting provides street and outdoor lighting services to customers in the Dayton region. DPL's subsidiaries are all wholly-owned. DPL also has a wholly-owned business trust, DPL Capital Trust II, formed for the purpose of issuing trust capital securities to investors. AES Ohio’s electric transmission and distribution businesses are subject to rate regulation by federal and state regulators. Accordingly, AES Ohio applies the accounting standards for regulated operations to its electric transmission and distribution businesses and records regulatory assets when incurred costs are expected to be recovered in future customer rates and regulatory liabilities when current cost recoveries in customer rates relate to expected future costs or overcollections of riders. Agreement to Sell Minority Interest in AES Ohio On September 13, 2024, DPL entered into (i) a Purchase and Sale Agreement with Astrid Holdings LP ("Investor"), a wholly-owned subsidiary of Caisse de dépôt et placement du Québec ("CDPQ"), pursuant to which DPL agreed to sell to Investor 15% of the issued and outstanding shares of common stock, no par value per share, of AES Ohio Holdings, Inc. ("Ohio Holdings" and, such agreement, the "Ohio Holdings Purchase Agreement") for a purchase price of approximately $273 million, subject to adjustment, and (ii) a Purchase and Sale Agreement with Investor, pursuant to which DPL agreed to sell to Investor 17.65% of the issued and outstanding shares of common stock, no par value per share, of AES Ohio Investments, Inc. ("Ohio Investments" and, such agreement, the "Ohio Investments Purchase Agreement" and together with the Ohio Holdings Purchase Agreement, the "Purchase Agreements") for a purchase price of approximately $273 million, subject to adjustment. Upon consummation of the transactions contemplated by the Ohio Holdings Purchase Agreement and the Ohio Investments Purchase Agreement together, the ("Closings"), CDPQ will own an aggregate indirect equity interest in AES Ohio of approximately 30%, with total proceeds to DPL of approximately $546 million, subject to adjustment. It is anticipated that the Closings will occur on the same day in the first half of 2025. There will be no change in management or operational control of DPL, Ohio Investments, Ohio Holdings or AES Ohio as a result of these transactions. The purchases and sales of the shares of capital stock of each of Ohio Holdings and Ohio Investments contemplated under each of the Purchase Agreements are subject to the satisfaction of certain customary conditions described in the Purchase Agreements, including, among others, receipt of the approval of the Public Utilities Commission of Ohio, the Federal Energy Regulatory Commission and completion of review by the Committee on Foreign Investments in the United States. In addition, each of the parties to the Purchase Agreements has agreed to customary covenants therein. In connection with the Closings, Investor, Ohio Investments and DPL will enter into a Shareholders' Agreement with respect to Ohio Investments (the "Shareholders' Agreement"), the form of which has been agreed to by the parties. The Shareholders' Agreement will establish the general framework governing the relationship between and among Investor and the Company, and their respective successors and transferees, as shareholders of Ohio Investments. In addition, Investor, Ohio Holdings and Ohio Investments will also enter into a Shareholders' Agreement with respect to Ohio Holdings with substantially identical terms.
Financial Statement Presentation	DPL’s Condensed Consolidated Financial Statements include the accounts of DPL and its wholly-owned subsidiaries except for DPL Capital Trust II, which is not consolidated consistent with the provisions of GAAP. All material intercompany accounts and transactions are eliminated in consolidation. We have evaluated subsequent events through the date this report was issued. Interim Financial Presentation The accompanying unaudited condensed consolidated financial statements and footnotes have been prepared in accordance with GAAP, as contained in the FASC, for interim financial information and Article 10 of Regulation S-X issued by the SEC. Accordingly, they do not include all the information and footnotes required by GAAP for annual fiscal reporting periods. In the opinion of management, the interim financial information includes all adjustments of a normal recurring nature necessary for a fair presentation of the results of operations, financial position, comprehensive income or loss, changes in shareholder's equity, and cash flows. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of expected results for the year ending December 31, 2024. The accompanying condensed consolidated financial statements are unaudited and should be read in conjunction with the 2023 audited consolidated financial statements and footnotes thereto, which are included in our Form 10-K. Use of Management Estimates The preparation of consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities and the revenue and expenses of the periods reported. Actual results could differ from these estimates and assumptions. Significant items subject to such estimates and assumptions include: the carrying value of property, plant and equipment; unbilled revenue; the valuation of allowances for credit losses and deferred income taxes; regulatory assets and liabilities; reserves recorded for income tax exposures; litigation; contingencies; and assets and liabilities related to employee benefits.
Accounting for Taxes Collected from Customers and Remitted to Governmental Authorities	AES Ohio collects certain excise taxes levied by state or local governments from its customers. These taxes are accounted for on a net basis and not included in revenue. The amounts of such taxes collected for the three and nine months ended September 30, 2024 and 2023 were as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Excise taxes collected $ 13.2 $ 12.8 $ 37.2 $ 35.4
Recently Issued Accounting Standards	New Accounting Pronouncements Issued But Not Yet Effective The following table provides a brief description of recent accounting pronouncements that could have an impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our consolidated financial statements.
Subsidiaries [Member]
Significant Accounting Policies [Line Items]
Inventory, Policy	Inventories Inventories consist of materials and supplies as of September 30, 2024 and December 31, 2023.
Description of Business	DP&L, which does business as AES Ohio, is a public utility incorporated in 1911 under the laws of Ohio. Beginning in 2001, Ohio law gave Ohio consumers the right to choose the electric generation supplier from whom they purchase retail generation service; however, retail transmission and distribution services are still regulated. AES Ohio has the exclusive right to provide such transmission and distribution services to approximately 541,000 customers located in West Central Ohio. Principal industries located in AES Ohio’s service territory include automotive, food processing, paper, plastic, manufacturing and defense. AES Ohio also provides retail SSO electric service to residential, commercial, industrial and governmental customers in a 6,000-square mile area of West Central Ohio. AES Ohio sources all of the generation for its SSO customers through a competitive bid process. AES Ohio's sales reflect the general economic conditions, seasonal weather patterns of the area, the market price of electricity and customer energy efficiency initiatives. AES Ohio owns numerous transmission facilities. AES Ohio records revenue and expenses for its proportional share of energy and capacity from its investment in OVEC. AES Ohio has one reportable segment, the Utility segment. In addition to AES Ohio's electric transmission and distribution businesses, the Utility segment includes revenue and expenses associated with AES Ohio's investment in OVEC. AES Ohio is a subsidiary of DPL. The terms “we,” “us,” “our” and “ours” are used to refer to AES Ohio. AES Ohio’s electric transmission and distribution businesses are subject to rate regulation by federal and state regulators. Accordingly, AES Ohio applies the accounting standards for regulated operations to its electric transmission and distribution businesses and records regulatory assets when incurred costs are expected to be recovered in future customer rates and regulatory liabilities when current cost recoveries in customer rates relate to expected future costs or overcollections of riders. Agreement to Sell Minority Interest in AES Ohio On September 13, 2024, DPL entered into (i) a Purchase and Sale Agreement with Astrid Holdings LP ("Investor"), a wholly-owned subsidiary of Caisse de dépôt et placement du Québec ("CDPQ"), pursuant to which DPL agreed to sell to Investor 15% of the issued and outstanding shares of common stock, no par value per share, of AES Ohio Holdings, Inc. ("Ohio Holdings" and, such agreement, the "Ohio Holdings Purchase Agreement") for a purchase price of approximately $273 million, subject to adjustment, and (ii) a Purchase and Sale Agreement with Investor, pursuant to which DPL agreed to sell to Investor 17.65% of the issued and outstanding shares of common stock, no par value per share, of AES Ohio Investments, Inc. ("Ohio Investments" and, such agreement, the "Ohio Investments Purchase Agreement" and together with the Ohio Holdings Purchase Agreement, the "Purchase Agreements") for a purchase price of approximately $273 million, subject to adjustment. Upon consummation of the transactions contemplated by the Ohio Holdings Purchase Agreement and the Ohio Investments Purchase Agreement together, the ("Closings"), CDPQ will own an aggregate indirect equity interest in AES Ohio of approximately 30%, with total proceeds to DPL of approximately $546 million, subject to adjustment. It is anticipated that the Closings will occur on the same day in the first half of 2025. There will be no change in management or operational control of DPL, Ohio Investments, Ohio Holdings or AES Ohio as a result of these transactions. The purchases and sales of the shares of capital stock of each of Ohio Holdings and Ohio Investments contemplated under each of the Purchase Agreements are subject to the satisfaction of certain customary conditions described in the Purchase Agreements, including, among others, receipt of the approval of the Public Utilities Commission of Ohio, the Federal Energy Regulatory Commission and completion of review by the Committee on Foreign Investments in the United States. In addition, each of the parties to the Purchase Agreements has agreed to customary covenants therein. In connection with the Closings, Investor, Ohio Investments and DPL will enter into a Shareholders' Agreement with respect to Ohio Investments (the "Shareholders' Agreement"), the form of which has been agreed to by the parties. The Shareholders' Agreement will establish the general framework governing the relationship between and among Investor and the Company, and their respective successors and transferees, as shareholders of Ohio Investments. In addition, Investor, Ohio Holdings and Ohio Investments will also enter into a Shareholders' Agreement with respect to Ohio Holdings with substantially identical terms.
Financial Statement Presentation	Financial Statement Presentation AES Ohio does not have any subsidiaries. We have evaluated subsequent events through the date this report was issued. Interim Financial Presentation The accompanying unaudited condensed financial statements and footnotes have been prepared in accordance with GAAP, as contained in the FASC, for interim financial information and Article 10 of Regulation S-X issued by the SEC. Accordingly, they do not include all the information and footnotes required by GAAP for annual fiscal reporting periods. In the opinion of management, the interim financial information includes all adjustments of a normal recurring nature necessary for a fair presentation of the results of operations, financial position, comprehensive income or loss, changes in shareholder's equity, and cash flows. The results of operations for the three and nine months ended September 30, 2024 are not necessarily indicative of expected results for the year ending December 31, 2024. The accompanying condensed financial statements are unaudited and should be read in conjunction with the 2023 audited financial statements and footnotes thereto, which are included in our Form 10-K. Use of Management Estimates The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities and the revenue and expenses of the periods reported. Actual results could differ from these estimates and assumptions. Significant items subject to such estimates and assumptions include: the carrying value of property, plant and equipment; unbilled revenue; the valuation of allowances for credit losses and deferred income taxes; regulatory assets and liabilities; reserves recorded for income tax exposures; litigation; contingencies; and assets and liabilities related to employee benefits.
Accounting for Taxes Collected from Customers and Remitted to Governmental Authorities	AES Ohio collects certain excise taxes levied by state or local governments from its customers. These taxes are accounted for on a net basis and not included in revenue. The amounts of such taxes collected for the three and nine months ended September 30, 2024 and 2023 were as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Excise taxes collected $ 13.2 $ 12.8 $ 37.2 $ 35.4
Recently Issued Accounting Standards	New Accounting Pronouncements Issued But Not Yet Effective The following table provides a brief description of recent accounting pronouncements that could have an impact on our financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our consolidated financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2023-07 Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures The amendments in this section are designed to improve the disclosures related to segment reporting on an interim and annual basis. Public companies must disclose significant segment expenses and an amount for other segment items. This will also require that a company disclose its annual disclosures under Topic 280 in each interim period. Furthermore, companies will need to disclose the Chief Operating Decision Maker (“CODM”) and how the CODM assesses the performance of a segment. Lastly, public companies that have a single reportable segment must report the required disclosures under Topic 280. The amendments in this Update are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. This ASU only affects disclosures, which will be provided when the amendment becomes effective. 2023-09 Income Taxes (Topic 740): Improvements to Income Tax Disclosures The amendments in this Update require that public business entities on an annual basis (1) disclose specific categories in the rate reconciliation and (2) provide additional information for reconciling items that meet a quantitative threshold. Furthermore, companies are required to disclose a disaggregated amount of income taxes paid at a federal, state, and foreign level as well as a breakdown of income taxes paid in a jurisdiction that comprises 5% of a company's total income taxes paid. Lastly, this ASU requires that companies disclose income (loss) from continuing operations before income tax at a domestic and foreign level and that companies disclose income tax expense from continuing operations on a federal, state, and foreign level. The amendments in this Update are effective for fiscal years beginning after December 15, 2024. This ASU only affects disclosures, which will be provided when the amendment becomes effective.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2024
Related Party Transaction [Line Items]
Allowance For Funds Used During Construction / Capitalized Interest	AES Ohio capitalizes an allowance for the net cost of funds (interest on borrowed funds and a reasonable rate of return on equity funds) used for construction purposes during the period of construction with a corresponding credit to income. During the three and nine months ended September 30, 2024 and 2023, AFUDC equity and AFUDC debt were as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 AFUDC equity $ 1.4 $ 1.3 $ 5.4 $ 3.8 AFUDC debt $ 1.8 $ 1.6 $ 6.3 $ 4.5
Schedule of Accumulated Other Comprehensive Income (Loss)	The changes in the components of AOCL during the nine months ended September 30, 2024 are as follows: $ in millions Change in cash flow hedges Change in unfunded pension and other postretirement obligations Total Balance as of January 1, 2024 $ 11.2 $ (15.8) $ (4.6) Amounts reclassified from AOCL to earnings (0.6) 0.1 (0.5) Balance as of September 30, 2024 $ 10.6 $ (15.7) $ (5.1)
Schedule of Supplemental Financial Information	The following table summarizes accounts receivable as of September 30, 2024 and December 31, 2023: $ in millions September 30, 2024 December 31, 2023 Accounts receivable, net: Customer receivables $ 75.5 $ 71.0 Unbilled revenue 18.8 19.4 Amounts due from affiliates 2.2 0.8 Other 6.7 2.2 Allowance for credit losses (1.8) (0.9) Total accounts receivable, net $ 101.4 $ 92.5
Accounts Receivable, Allowance for Credit Loss	The following table is a roll forward of our allowance for credit losses related to the accounts receivable balances for the nine months ended September 30, 2024 and 2023: Nine months ended September 30, $ in millions 2024 2023 Allowance for credit losses: Beginning balance $ 0.9 $ 0.5 Current period provision 3.8 4.1 Write-offs charged against allowance (3.5) (4.4) Recoveries collected 0.6 0.8 Ending balance $ 1.8 $ 1.0
New Accounting Pronouncements, Policy [Policy Text Block]	New Accounting Pronouncements Issued But Not Yet Effective The following table provides a brief description of recent accounting pronouncements that could have an impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our consolidated financial statements.
Schedule of Cash and Cash Equivalents [Table Text Block]	The following table summarizes cash, cash equivalents, and restricted cash amounts reported on the Condensed Consolidated Balance Sheets that reconcile to the total of such amounts as shown on the Condensed Consolidated Statements of Cash Flows: $ in millions September 30, 2024 December 31, 2023 Cash and cash equivalents $ 41.0 $ 41.0 Restricted cash (included in Prepayments and other current assets ) 0.1 0.1 Total cash, cash equivalents and restricted cash $ 41.1 $ 41.1
Schedule of New Accounting Pronouncements	New Accounting Pronouncements Issued But Not Yet Effective The following table provides a brief description of recent accounting pronouncements that could have an impact on our consolidated financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our consolidated financial statements.
Subsidiaries [Member]
Related Party Transaction [Line Items]
Allowance For Funds Used During Construction / Capitalized Interest	AFUDC AES Ohio capitalizes an allowance for the net cost of funds (interest on borrowed funds and a reasonable rate of return on equity funds) used for construction purposes during the period of construction with a corresponding credit to income. During the three and nine months ended September 30, 2024 and 2023, AFUDC equity and AFUDC debt were as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 AFUDC equity $ 1.4 $ 1.3 $ 5.4 $ 3.8 AFUDC debt $ 1.8 $ 1.6 $ 6.3 $ 4.5
Schedule of Accumulated Other Comprehensive Income (Loss)	The changes in the components of AOCL during the nine months ended September 30, 2024 are as follows: $ in millions Change in Accumulated other comprehensive loss Balance as of January 1, 2024 $ (27.9) Amounts reclassified from AOCL to earnings 1.2 Balance as of September 30, 2024 $ (26.7)
Schedule of Supplemental Financial Information	The following table summarizes accounts receivable as of September 30, 2024 and December 31, 2023: $ in millions September 30, 2024 December 31, 2023 Accounts receivable, net: Customer receivables $ 74.6 $ 70.0 Unbilled revenue 18.8 19.4 Amounts due from affiliates 2.9 2.4 Other 6.6 2.2 Allowance for credit losses (1.8) (0.9) Total accounts receivable, net $ 101.1 $ 93.1
Accounts Receivable, Allowance for Credit Loss	The following table is a roll forward of our allowance for credit losses related to the accounts receivable balances for the nine months ended September 30, 2024 and 2023: Nine months ended September 30, $ in millions 2024 2023 Allowance for credit losses: Beginning balance $ 0.9 $ 0.5 Current period provision 3.8 4.1 Write-offs charged against allowance (3.5) (4.4) Recoveries collected 0.6 0.8 Ending balance $ 1.8 $ 1.0
New Accounting Pronouncements, Policy [Policy Text Block]	New Accounting Pronouncements Issued But Not Yet Effective The following table provides a brief description of recent accounting pronouncements that could have an impact on our financial statements. Accounting pronouncements not listed below were assessed and determined to be either not applicable or are expected to have no material impact on our consolidated financial statements. ASU Number and Name Description Date of Adoption Effect on the financial statements upon adoption 2023-07 Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures The amendments in this section are designed to improve the disclosures related to segment reporting on an interim and annual basis. Public companies must disclose significant segment expenses and an amount for other segment items. This will also require that a company disclose its annual disclosures under Topic 280 in each interim period. Furthermore, companies will need to disclose the Chief Operating Decision Maker (“CODM”) and how the CODM assesses the performance of a segment. Lastly, public companies that have a single reportable segment must report the required disclosures under Topic 280. The amendments in this Update are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. This ASU only affects disclosures, which will be provided when the amendment becomes effective. 2023-09 Income Taxes (Topic 740): Improvements to Income Tax Disclosures The amendments in this Update require that public business entities on an annual basis (1) disclose specific categories in the rate reconciliation and (2) provide additional information for reconciling items that meet a quantitative threshold. Furthermore, companies are required to disclose a disaggregated amount of income taxes paid at a federal, state, and foreign level as well as a breakdown of income taxes paid in a jurisdiction that comprises 5% of a company's total income taxes paid. Lastly, this ASU requires that companies disclose income (loss) from continuing operations before income tax at a domestic and foreign level and that companies disclose income tax expense from continuing operations on a federal, state, and foreign level. The amendments in this Update are effective for fiscal years beginning after December 15, 2024. This ASU only affects disclosures, which will be provided when the amendment becomes effective.
Schedule of Cash and Cash Equivalents [Table Text Block]	The following table summarizes cash, cash equivalents, and restricted cash amounts reported on the Condensed Balance Sheets that reconcile to the total of such amounts as shown on the Condensed Statements of Cash Flows: $ in millions September 30, 2024 December 31, 2023 Cash and cash equivalents $ 19.6 $ 15.5 Restricted cash (included in Prepayments and other current assets ) 0.1 0.1 Total cash, cash equivalents and restricted cash $ 19.7 $ 15.6

Fair Value (Tables)

Fair Value (Tables)	9 Months Ended
	Sep. 30, 2024
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized Gain (Loss) on Investments	AES Ohio established a Master Trust to hold assets that could be used for the benefit of employees participating in employee benefit plans. These assets are not used for general operating purposes. These assets are primarily comprised of open-ended mutual funds, which are valued using the net asset value per unit. These assets are recorded at fair value within Other non-current assets on the Condensed Consolidated Balance Sheets and are classified as equity investments. Net unrealized gains / (losses) related to equity investments still held as of September 30, 2024 and 2023 are as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Net unrealized gains / (losses) (a) $ 0.4 $ (0.2) $ 0.7 $ 0.2 (a) These amounts are included in Other income, net in our Condensed Consolidated Statements of Operations.
Fair Value Measurement Inputs and Valuation Techniques	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 Condensed Consolidated Balance Sheets as of the periods indicated, but for which fair value is disclosed: September 30, 2024 December 31, 2023 Carrying Amount Fair Value Carrying Amount Fair Value $ in millions Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Liabilities Long-term debt $ 1,839.3 $ — $ 1,725.2 $ 16.7 $ 1,741.9 $ 1,837.6 $ — $ 1,706.2 $ 16.8 $ 1,723.0
Fair Value of Assets and Liabilities Measured on Recurring Basis	The fair value of assets and liabilities as of September 30, 2024 and December 31, 2023 measured on a recurring basis and the respective category within the fair value hierarchy for DPL is as follows: Fair value as of September 30, 2024 Fair value as of December 31, 2023 $ in millions Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Master Trust assets Money market funds $ 0.3 $ — $ — $ 0.3 $ 0.6 $ — $ — $ 0.6 Mutual funds 7.8 — — 7.8 7.2 — — 7.2 Total assets $ 8.1 $ — $ — $ 8.1 $ 7.8 $ — $ — $ 7.8
Subsidiaries [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized Gain (Loss) on Investments	AES Ohio established a Master Trust to hold assets that could be used for the benefit of employees participating in employee benefit plans. These assets are not used for general operating purposes. These assets are primarily comprised of open-ended mutual funds, which are valued using the net asset value per unit. These assets are recorded at fair value within Other non-current assets on the Condensed Balance Sheets and are classified as equity investments. Net unrealized gains / (losses) related to equity investments still held as of September 30, 2024 and 2023 are as follows: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Net unrealized gains (a) $ 0.4 $ (0.2) $ 0.7 $ 0.2 (a) These amounts are included in Other income, net in our Condensed Statements of Operations.
Fair Value Measurement Inputs and Valuation Techniques	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 Condensed Balance Sheets as of the periods indicated, but for which fair value is disclosed: September 30, 2024 December 31, 2023 Carrying Amount Fair Value Carrying Amount Fair Value $ in millions Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Liabilities Long-term debt $ 1,012.8 $ — $ 918.8 $ 16.7 $ 935.5 $ 1,012.5 $ — $ 909.9 $ 16.8 $ 926.7
Fair Value of Assets and Liabilities Measured on Recurring Basis	The fair value of assets and liabilities as of September 30, 2024 and December 31, 2023 measured on a recurring basis and the respective category within the fair value hierarchy for AES Ohio is as follows: Fair value as of September 30, 2024 Fair value as of December 31, 2023 $ in millions Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total Assets Master Trust assets Money market funds $ 0.3 $ — $ — $ 0.3 $ 0.6 $ — $ — $ 0.6 Mutual funds 7.8 — — 7.8 7.2 — — 7.2 Total assets $ 8.1 $ — $ — $ 8.1 $ 7.8 $ — $ — $ 7.8

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Gains or Losses Recognized in AOCI for the Cash Flow Hedges	The following tables provide information concerning gains recognized in AOCL for the cash flow hedges for the three and nine months ended September 30, 2024 and 2023: Three months ended Nine months ended September 30, September 30, 2024 2023 2024 2023 Interest Interest Interest Interest $ in millions (net of tax) Rate Hedge Rate Hedge Rate Hedge Rate Hedge Beginning accumulated derivative gains in AOCL $ 10.7 $ 11.6 $ 11.2 $ 12.0 Net gains reclassified to earnings Interest expense (0.1) (0.2) (0.6) (0.6) Ending accumulated derivative gains in AOCL $ 10.6 $ 11.4 $ 10.6 $ 11.4 Portion expected to be reclassified to earnings in the next twelve months $ (0.8)

Debt (Tables)

Debt (Tables)	9 Months Ended
	Sep. 30, 2024
Debt Instrument [Line Items]
Long-term Debt	DEBT Long-term debt is as follows: Interest September 30, December 31, $ in millions Rate Due 2024 2023 AES Ohio debt First Mortgage Bonds 3.95 % 2049 $ 425.0 $ 425.0 First Mortgage Bonds 3.20 % 2040 140.0 140.0 First Mortgage Bonds 5.70 % 2033 107.5 107.5 First Mortgage Bonds 5.19 % 2033 100.0 100.0 First Mortgage Bonds 5.49 % 2028 92.5 92.5 Tax-exempt First Mortgage Bonds (a) 4.25 % 2027 100.0 100.0 Tax-exempt First Mortgage Bonds (b) 4.00 % 2027 40.0 40.0 U.S. Government note 4.20 % 2061 16.7 16.8 Unamortized deferred financing costs (6.6) (7.1) Unamortized debt discounts (2.3) (2.2) Total long-term debt at AES Ohio 1,012.8 1,012.5 DPL Inc. debt Senior unsecured notes 4.125 % 2025 415.0 415.0 Senior unsecured notes 4.35 % 2029 400.0 400.0 Note to DPL Capital Trust II (c) 8.125 % 2031 15.6 15.6 Unamortized deferred financing costs (3.5) (4.9) Unamortized debt discounts (0.6) (0.6) Total DPL consolidated long-term debt 1,839.3 1,837.6 Less: current portion (414.0) (0.2) DPL consolidated long-term debt, net of current portion $ 1,425.3 $ 1,837.4 (a) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of November 1, 2040 but are subject to a mandatory put in June 2027. (b) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of January 1, 2034 but are subject to a mandatory put in June 2027. (c) Note payable to related party. Revolving credit agreements As of September 30, 2024 and December 31, 2023, the AES Ohio Credit Agreement had outstanding borrowings of $45.0 million and $15.0 million, respectively. Significant Transactions In August 2024, AES Ohio entered into an unsecured $150.0 million 364-day term loan agreement ("AES Ohio Term Loan"). The AES Ohio Term Loan was fully drawn at closing with the proceeds being used for general corporate purposes. This agreement matures on August 13, 2025, and bears interest at variable rates as described in the $150 million Term Loan Agreement. The AES Ohio Term Loan contains customary representations, warranties and covenants, including a leverage covenant consistent with the leverage covenant contained in AES Ohio's Credit Agreement. AES Ohio has classified the AES Ohio Term Loan as short-term indebtedness as it matures in August 2025. Management plans to repay the AES Ohio Term Loan Agreement through a combination of funds from debt financings and parent equity capital contributions. DPL's Senior unsecured notes DPL has $415.0 million of 4.125% Senior unsecured notes due July 1, 2025 ("2025 DPL Notes"). Although current liquid funds are not sufficient to repay the amounts due under the 2025 DPL Notes at maturity, we will use a portion of the proceeds from the Closings to repay the notes in full (see Note 1. Overview and Summary of Significant Accounting Policies - Agreement to Sell Minority Interest in AES Ohio for more information). Long-term debt covenants and restrictions The AES Ohio Credit Agreement, AES Ohio Term Loan, and Fifty-Third, Fifty-Fourth and Fifty-Fifth Supplemental Indentures to the First Mortgage, pursuant to which the 3.20% Bonds due 2040, the 5.19% Bonds due 2033, the 5.49% Bonds due 2028 and the 5.70% Bonds due 2033 were issued, respectively, each contain one financial covenant. The covenant measures Total Debt to Total Capitalization and is calculated, at the end of each fiscal quarter, by dividing total debt at the end of the quarter by total capitalization at the end of the quarter. AES Ohio’s Total Debt to Total Capitalization ratio shall not be greater than 0.67 to 1.00. As of September 30, 2024, AES Ohio was in compliance with this financial covenant. AES Ohio does not have any meaningful restrictions in its debt financing documents prohibiting dividends and return of capital payments to its parent, DPL. As of September 30, 2024, AES Ohio was in compliance with all debt covenants, including the financial covenant described above. Substantially all property, plant & equipment of AES Ohio is subject to the lien of the mortgage securing AES Ohio’s First and Refunding Mortgage.
Schedule of Long-term Debt Instruments	: Interest September 30, December 31, $ in millions Rate Due 2024 2023 AES Ohio debt First Mortgage Bonds 3.95 % 2049 $ 425.0 $ 425.0 First Mortgage Bonds 3.20 % 2040 140.0 140.0 First Mortgage Bonds 5.70 % 2033 107.5 107.5 First Mortgage Bonds 5.19 % 2033 100.0 100.0 First Mortgage Bonds 5.49 % 2028 92.5 92.5 Tax-exempt First Mortgage Bonds (a) 4.25 % 2027 100.0 100.0 Tax-exempt First Mortgage Bonds (b) 4.00 % 2027 40.0 40.0 U.S. Government note 4.20 % 2061 16.7 16.8 Unamortized deferred financing costs (6.6) (7.1) Unamortized debt discounts (2.3) (2.2) Total long-term debt at AES Ohio 1,012.8 1,012.5 DPL Inc. debt Senior unsecured notes 4.125 % 2025 415.0 415.0 Senior unsecured notes 4.35 % 2029 400.0 400.0 Note to DPL Capital Trust II (c) 8.125 % 2031 15.6 15.6 Unamortized deferred financing costs (3.5) (4.9) Unamortized debt discounts (0.6) (0.6) Total DPL consolidated long-term debt 1,839.3 1,837.6 Less: current portion (414.0) (0.2) DPL consolidated long-term debt, net of current portion $ 1,425.3 $ 1,837.4 (a) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of November 1, 2040 but are subject to a mandatory put in June 2027. (b) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of January 1, 2034 but are subject to a mandatory put in June 2027. (c) Note payable to related party.
Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term Debt	DEBT Long-term debt is as follows: Interest September 30, December 31, $ in millions Rate Due 2024 2023 First Mortgage Bonds 3.95 % 2049 $ 425.0 $ 425.0 First Mortgage Bonds 3.20 % 2040 140.0 140.0 First Mortgage Bonds 5.70 % 2033 107.5 107.5 First Mortgage Bonds 5.19 % 2033 100.0 100.0 First Mortgage Bonds 5.49 % 2028 92.5 92.5 Tax-exempt First Mortgage Bonds (a) 4.25 % 2027 100.0 100.0 Tax-exempt First Mortgage Bonds (b) 4.00 % 2027 40.0 40.0 U.S. Government note 4.20 % 2061 16.7 16.8 Unamortized deferred financing costs (6.6) (7.1) Unamortized debt discounts (2.3) (2.2) Total long-term debt 1,012.8 1,012.5 Less: current portion (0.2) (0.2) Long-term debt, net of current portion $ 1,012.6 $ 1,012.3 (a) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of November 1, 2040 but are subject to a mandatory put in June 2027. (b) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of January 1, 2034 but are subject to a mandatory put in June 2027. Revolving credit agreements As of September 30, 2024 and December 31, 2023, the AES Ohio Credit Agreement had outstanding borrowings of $45.0 million and $15.0 million, respectively. Significant Transactions In August 2024, AES Ohio entered into an unsecured $150.0 million 364-day term loan agreement ("AES Ohio Term Loan"). The AES Ohio Term Loan was fully drawn at closing with the proceeds being used for general corporate purposes. This agreement matures on August 13, 2025, and bears interest at variable rates as described in the $150 million Term Loan Agreement. The AES Ohio Term Loan contains customary representations, warranties and covenants, including a leverage covenant consistent with the leverage covenant contained in AES Ohio's Credit Agreement. AES Ohio has classified the AES Ohio Term Loan as short-term indebtedness as it matures in August 2025. Management plans to repay the AES Ohio Term Loan Agreement through a combination of funds from debt financings and parent equity capital contributions. Long-term debt covenants and restrictions The AES Ohio Credit Agreement, AES Ohio Term Loan, and Fifty-Third, Fifty-Fourth and Fifty-Fifth Supplemental Indentures to the First Mortgage, pursuant to which the 3.20% Bonds due 2040, the 5.19% Bonds due 2033, the 5.49% Bonds due 2028 and the 5.70% Bonds due 2033 were issued, respectively, each contain one financial covenant. The covenant measures Total Debt to Total Capitalization and is calculated, at the end of each fiscal quarter, by dividing total debt at the end of the quarter by total capitalization at the end of the quarter. AES Ohio’s Total Debt to Total Capitalization ratio shall not be greater than 0.67 to 1.00. As of September 30, 2024, AES Ohio was in compliance with this financial covenant. As of September 30, 2024, AES Ohio was in compliance with all debt covenants, including the financial covenant described above. AES Ohio does not have any meaningful restrictions in its debt financing documents prohibiting dividends and return of capital payments to its parent, DPL. Substantially all property, plant & equipment of AES Ohio is subject to the lien of the mortgage securing AES Ohio’s First and Refunding Mortgage.
Schedule of Long-term Debt Instruments	Interest September 30, December 31, $ in millions Rate Due 2024 2023 First Mortgage Bonds 3.95 % 2049 $ 425.0 $ 425.0 First Mortgage Bonds 3.20 % 2040 140.0 140.0 First Mortgage Bonds 5.70 % 2033 107.5 107.5 First Mortgage Bonds 5.19 % 2033 100.0 100.0 First Mortgage Bonds 5.49 % 2028 92.5 92.5 Tax-exempt First Mortgage Bonds (a) 4.25 % 2027 100.0 100.0 Tax-exempt First Mortgage Bonds (b) 4.00 % 2027 40.0 40.0 U.S. Government note 4.20 % 2061 16.7 16.8 Unamortized deferred financing costs (6.6) (7.1) Unamortized debt discounts (2.3) (2.2) Total long-term debt 1,012.8 1,012.5 Less: current portion (0.2) (0.2) Long-term debt, net of current portion $ 1,012.6 $ 1,012.3 (a) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of November 1, 2040 but are subject to a mandatory put in June 2027. (b) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of January 1, 2034 but are subject to a mandatory put in June 2027. Revolving credit agreements

Benefit Plans (Tables)

Benefit Plans (Tables)	9 Months Ended
	Sep. 30, 2024
Entity Information [Line Items]
Schedule of Net Periodic Benefit Cost / (Income)	The following table presents the net periodic benefit cost of the Pension Plans for the three and nine months ended September 30, 2024 and 2023: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Service cost $ 0.7 $ 0.8 $ 1.9 $ 2.2 Interest cost 3.6 3.9 11.0 11.9 Expected return on plan assets (3.7) (4.4) (11.1) (13.2) Amortization of unrecognized: Prior service cost 0.2 0.3 0.7 0.8 Actuarial loss 0.5 0.2 1.6 0.5 Net periodic benefit cost $ 1.3 $ 0.8 $ 4.1 $ 2.2
Subsidiaries [Member]
Entity Information [Line Items]
Schedule of Net Periodic Benefit Cost / (Income)	The following table presents the net periodic benefit cost of the Pension Plans for the three and nine months ended September 30, 2024 and 2023: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Service cost $ 0.7 $ 0.8 $ 1.9 $ 2.2 Interest cost 3.6 3.9 11.0 11.9 Expected return on plan assets (3.7) (4.4) (11.1) (13.2) Amortization of unrecognized: Prior service cost 0.3 0.2 0.7 0.8 Actuarial loss 0.9 0.3 2.9 0.9 Net periodic benefit cost $ 1.8 $ 0.8 $ 5.4 $ 2.6

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2024
Segment Reporting Information [Line Items]
Financial Reporting for Reportable Business Segments	The following tables present financial information for DPL’s reportable business segment: $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Three months ended September 30, 2024 Revenue from external customers $ 225.1 $ 2.4 $ — $ 227.5 Intersegment revenue 0.3 1.2 (1.5) — Total revenue $ 225.4 $ 3.6 $ (1.5) $ 227.5 Depreciation and amortization $ 25.2 $ 0.5 $ — $ 25.7 Interest expense, net $ 11.8 $ 9.3 $ — $ 21.1 Income / (loss) before income tax $ 10.6 $ (7.8) $ — $ 2.8 $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Three Months Ended September 30, 2023 Revenue from external customers $ 221.8 $ 2.4 $ — $ 224.2 Intersegment revenue 0.2 1.5 (1.7) — Total revenue $ 222.0 $ 3.9 $ (1.7) $ 224.2 Depreciation and amortization $ 20.3 $ 0.3 $ — $ 20.6 Interest expense, net $ (1.3) $ 9.1 $ — $ 7.8 Income / (loss) before income tax $ 55.1 $ (6.9) $ — $ 48.2 $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Nine months ended September 30, 2024 Revenue from external customers $ 655.9 $ 7.2 $ — $ 663.1 Intersegment revenue 0.7 3.7 (4.4) — Total revenue $ 656.6 $ 10.9 $ (4.4) $ 663.1 Depreciation and amortization $ 68.0 $ 1.4 $ — $ 69.4 Interest expense, net $ 34.7 $ 27.5 $ — $ 62.2 Income / (loss) before income tax $ 41.2 $ (22.7) $ — $ 18.5 $ in millions Utility Other Adjustments and Eliminations DPL Consolidated Nine months ended September 30, 2023 Revenue from external customers $ 659.0 $ 7.3 $ — $ 666.3 Intersegment revenue 0.5 3.2 (3.7) — Total revenue $ 659.5 $ 10.5 $ (3.7) $ 666.3 Depreciation and amortization $ 59.9 $ 1.0 $ — $ 60.9 Interest expense, net $ 16.7 $ 28.5 $ — $ 45.2 Income / (loss) before income tax $ 64.1 $ (24.2) $ — $ 39.9 Total Assets ($ in millions) September 30, 2024 December 31, 2023 Utility $ 3,150.2 $ 2,871.0 All Other (a) 50.3 35.2 DPL Consolidated $ 3,200.5 $ 2,906.2 (a)

Revenue (Tables)

Revenue (Tables)	9 Months Ended
	Sep. 30, 2024
Disaggregation of Revenue [Table Text Block]	The following table presents our revenue from contracts with customers and other revenue by segment for the three and nine months ended September 30, 2024 and 2023: $ in millions Utility Other Adjustments and Eliminations Total Three Months Ended September 30, 2024 Retail revenue Retail revenue from contracts with customers Residential revenue $ 120.9 $ — $ — $ 120.9 Commercial revenue 41.9 — — 41.9 Industrial revenue 17.4 — — 17.4 Governmental revenue 7.4 — — 7.4 Other (a) 2.7 — — 2.7 Total retail revenue from contracts with customers 190.3 — — 190.3 Wholesale revenue Wholesale revenue from contracts with customers 4.5 — (0.2) 4.3 RTO ancillary revenue 27.0 — — 27.0 Capacity revenue 0.3 — — 0.3 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 2.4 — 2.4 Other miscellaneous revenue 3.3 1.2 (1.3) 3.2 Total revenue $ 225.4 $ 3.6 $ (1.5) $ 227.5 Three Months Ended September 30, 2023 Retail revenue Retail revenue from contracts with customers Residential revenue $ 127.8 $ — $ — $ 127.8 Commercial revenue 42.7 — — 42.7 Industrial revenue 16.5 — — 16.5 Governmental revenue 6.8 — — 6.8 Other (a) 3.5 — — 3.5 Total retail revenue from contracts with customers 197.3 — — 197.3 Other retail revenue (0.2) — — (0.2) Wholesale revenue Wholesale revenue from contracts with customers 4.2 — (0.2) 4.0 RTO ancillary revenue 21.4 0.1 — 21.5 Capacity revenue 0.7 — — 0.7 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 2.3 — 2.3 Other miscellaneous revenue (1.4) 1.5 (1.5) (1.4) Total revenue $ 222.0 $ 3.9 $ (1.7) $ 224.2 $ in millions Utility Other Adjustments and Eliminations Total Nine months ended September 30, 2024 Retail revenue Retail revenue from contracts with customers Residential revenue $ 347.1 $ — $ — $ 347.1 Commercial revenue 120.5 — — 120.5 Industrial revenue 50.1 — — 50.1 Governmental revenue 19.5 — — 19.5 Other (a) 9.0 — — 9.0 Total retail revenue from contracts with customers 546.2 — — 546.2 Other retail revenue — — — — Wholesale revenue Wholesale revenue from contracts with customers 12.3 — (0.7) 11.6 RTO ancillary revenue 89.0 — — 89.0 Capacity revenue 0.7 — — 0.7 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 7.2 — 7.2 Other miscellaneous revenue 8.4 3.7 (3.7) 8.4 Total revenue $ 656.6 $ 10.9 $ (4.4) $ 663.1 Nine months ended September 30, 2023 Retail revenue Retail revenue from contracts with customers Residential revenue $ 377.9 $ — $ — $ 377.9 Commercial revenue 124.8 — — 124.8 Industrial revenue 50.4 — — 50.4 Governmental revenue 18.7 — — 18.7 Other (a) 9.9 — — 9.9 Total retail revenue from contracts with customers 581.7 — — 581.7 Other retail revenue (0.2) — — (0.2) Wholesale revenue Wholesale revenue from contracts with customers 11.3 — (0.5) 10.8 RTO ancillary revenue 65.7 0.1 — 65.8 Capacity revenue 3.2 — — 3.2 Miscellaneous revenue Miscellaneous revenue from contracts with customers (b) — 7.2 — 7.2 Other miscellaneous revenue (2.2) 3.2 (3.2) (2.2) Total revenue $ 659.5 $ 10.5 $ (3.7) $ 666.3 (a ) "Other" primarily includes operation and maintenance service revenue, billing service fees from CRES providers and other miscellaneous retail revenue from contracts with customers. (b) Miscellaneous revenue from contracts with customers primarily includes revenue for various services provided by Miami Valley Lighting.
Subsidiaries [Member]
Disaggregation of Revenue [Table Text Block]	The following table presents our revenue from contracts with customers and other revenue for the three and nine months ended September 30, 2024 and 2023: Three months ended Nine months ended September 30, September 30, $ in millions 2024 2023 2024 2023 Retail revenue Retail revenue from contracts with customers Residential revenue $ 120.9 $ 127.8 $ 347.1 $ 377.9 Commercial revenue 41.9 42.7 120.5 124.8 Industrial revenue 17.4 16.5 50.1 50.4 Governmental revenue 7.4 6.8 19.5 18.7 Other (a) 2.7 3.5 9.0 9.9 Total retail revenue from contracts with customers 190.3 197.3 546.2 581.7 Other retail revenue — (0.2) — (0.2) Wholesale revenue Wholesale revenue from contracts with customers 4.5 4.2 12.3 11.3 RTO ancillary revenue 27.0 21.4 89.0 65.7 Capacity revenue 0.3 0.7 0.7 3.2 Miscellaneous revenue 3.3 (1.4) 8.4 (2.2) Total revenue $ 225.4 $ 222.0 $ 656.6 $ 659.5 (a ) "Other" primarily includes operation and maintenance service revenue, billing service fees from CRES providers and other miscellaneous retail revenue from contracts with customers.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Narrative) (Details) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)	Mar. 31, 2024 USD ($)	Sep. 30, 2023 USD ($)	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Sep. 30, 2024 USD ($) mi² customer segment	Sep. 30, 2023 USD ($)	Jan. 01, 2025 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Significant Accounting Policies [Line Items]
Cash and Cash Equivalents, at Carrying Value	$ 41						$ 41			$ 41
Restricted Cash	0.1						0.1			0.1
Excise taxes collected	13.2			$ 12.8			37.2	$ 35.4
Customer receivables	75.5						75.5			71
Unbilled Revenue	18.8						18.8			19.4
Accounts Receivable, Allowance for Credit Loss	(1.8)						(1.8)			(0.9)
Accounts Receivable, Allowance for Credit Loss, Current	1.8			1			1.8	1		0.9	$ 0.5
Accounts Receivable, Credit Loss Expense (Reversal)							3.8	4.1
Accounts Receivable, Allowance for Credit Loss, Writeoff							(3.5)	(4.4)
Accounts Receivable, Allowance for Credit Loss, Recovery							0.6	0.8
Interest expense	(21.1)			(7.8)			(62.2)	(45.2)
Income Tax Expense (Benefit)	7.5			(9.6)			4.6	(5.3)
Net income	(10.3)	$ (10.2)	$ (2.6)	(38.6)	$ 5.2	$ (1.2)	(23.1)	(34.6)
Nonoperating Income (Expense)	19.7			6.4			57.1	40.5
Accumulated other comprehensive income	(5.1)						(5.1)			(4.6)
Other Comprehensive Income (Loss), Net of Tax	(0.1)	(0.2)	(0.2)	(0.2)	(0.1)	(0.2)	(0.5)	(0.5)
Other Comprehensive Income (Loss), Defined Benefit Plan, Transition Asset (Obligation), Reclassification Adjustment from AOCI, after Tax	0			0			0.1	0.1
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax							(0.5)
Contract with Customer, Asset, before Allowance for Credit Loss	94.3						94.3			90.4
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	41.1			49.4			41.1	49.4		41.1	30.6
Accounts Receivable, after Allowance for Credit Loss, Current	101.4						101.4			92.5
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(0.1)			(0.2)			(0.6)	(0.6)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax	0			0			(0.1)	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	0.1			0			0.1	0.1
Allowance for Funds Used During Construction, Equity Portion	1.4			1.3			5.4	3.8
Allowance for Funds Used During Construction, Capitalized Interest	(1.8)			(1.6)			(6.3)	(4.5)
Unrealized Gain (Loss) on Investments	0.4			(0.2)			0.7	0.2
Forecast [Member]
Significant Accounting Policies [Line Items]
Ohio Holdings Purchase price									$ 273
Ohio Investments Purchase price									273
CDPQ Investment total									$ 546
Ohio Holdings Investment Percent									15%
Ohio Investment Percent									17.65%
CDPQ Investment percent									30%
Nonrelated Party
Significant Accounting Policies [Line Items]
Other	6.7						6.7			2.2
Related Party
Significant Accounting Policies [Line Items]
Other	2.2						2.2			0.8
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Significant Accounting Policies [Line Items]
Accumulated other comprehensive income	10.6						10.6			11.2
Change in unfunded pension obligation [Member]
Significant Accounting Policies [Line Items]
Accumulated other comprehensive income	(15.7)						$ (15.7)			(15.8)
Subsidiaries [Member]
Significant Accounting Policies [Line Items]
Number of reportable segments | segment							1
Cash and Cash Equivalents, at Carrying Value	19.6						$ 19.6			15.5
Restricted Cash	0.1						$ 0.1			0.1
Approximate number of retail customers | customer							541,000
Service area, square miles | mi²							6,000
Number of Operating Segments | segment							1
Excise taxes collected	13.2			12.8			$ 37.2	35.4
Customer receivables	74.6						74.6			70
Unbilled Revenue	18.8						18.8			19.4
Accounts Receivable, Allowance for Credit Loss	(1.8)						(1.8)			(0.9)
Accounts Receivable, Allowance for Credit Loss, Current	1.8			1			1.8	1		0.9	0.5
Accounts Receivable, Credit Loss Expense (Reversal)							3.8	4.1
Accounts Receivable, Allowance for Credit Loss, Writeoff							3.5	4.4
Interest expense	(11.8)			1.3			(34.7)	(16.7)
Income Tax Expense (Benefit)	1.9			(11.5)			(4.2)	(11.3)
Net income	(12.5)			(43.6)	0.4	(9.6)	(37)	(52.8)
Nonoperating Income (Expense)	11.1			(2.5)			31.5	12.7
Accumulated other comprehensive income	(26.7)						(26.7)			(27.9)
Other Comprehensive Income (Loss), Net of Tax	0.4	$ 0.4	$ 0.4	0.1	$ 0.1	$ 0.1	1.2	0.3
Other Comprehensive Income (Loss), Defined Benefit Plan, Transition Asset (Obligation), Reclassification Adjustment from AOCI, after Tax	0.4			0.1			1.2	0.3
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax							1.2
Contract with Customer, Asset, before Allowance for Credit Loss	93.4						93.4			89.4
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	19.7			33.1			19.7	33.1		15.6	$ 19.8
Accounts Receivable, after Allowance for Credit Loss, Current	101.1						101.1			93.1
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax				(0.1)			(0.4)	(0.2)
Allowance for Funds Used During Construction, Equity Portion	1.4			1.3			5.4	3.8
Allowance for Funds Used During Construction, Capitalized Interest	(1.8)			(1.6)			(6.3)	(4.5)
Unrealized Gain (Loss) on Investments	0.4			$ (0.2)			0.7	$ 0.2
Subsidiaries [Member] | Forecast [Member]
Significant Accounting Policies [Line Items]
Ohio Holdings Purchase price									$ 273
Ohio Investments Purchase price									273
CDPQ Investment total									$ 546
Ohio Holdings Investment Percent									15%
Ohio Investment Percent									17.65%
CDPQ Investment percent									30%
Subsidiaries [Member] | Nonrelated Party
Significant Accounting Policies [Line Items]
Other	6.6						6.6			2.2
Subsidiaries [Member] | Related Party
Significant Accounting Policies [Line Items]
Other	$ 2.9						$ 2.9			$ 2.4

Regulatory Matters (Details)

Regulatory Matters (Details) - USD ($) $ in Millions		9 Months Ended
	Jul. 01, 2025	Sep. 30, 2024	Dec. 31, 2023
Regulatory assets, non-current		$ 146.2	$ 155.7
Schedule of Regulatory Assets and Liabilities [Text Block]		REGULATORY MATTERS Smart Grid Phase 2 Plan
Forecast [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Smart Grid Phase 2 costs	$ 683
Estimated Smart Grid Phase 2 capital	240.5
Estimated Smart Grid Phase 2 O&M	18.6
Subsidiaries [Member]
Regulatory assets, non-current		$ 146.2	$ 155.7
Schedule of Regulatory Assets and Liabilities [Text Block]		REGULATORY MATTERS Smart Grid Phase 2 Plan In February 2024, AES Ohio filed a Smart Grid Phase 2 with the PUCO proposing to invest approximately $683 million in capital projects over a 10-year period following Smart Grid Phase 1, which ends June 2025. On September 13, 2024, AES Ohio reached a settlement with the PUCO Staff and other parties on the pending Smart Grid Phase 2 Application. The Settlement will provide for a four-year plan to invest $240.5 million of capital and $18.6 million of operations and maintenance expense related to grid modernization, support of Distributed Energy Resources and Economic Development and an enhanced Telecommunications network. These costs will be recovered through the existing Investment Infrastructure Rider. If approved, AES Ohio will implement a comprehensive grid modernization project that will deliver benefits to customers, society as a whole and to AES Ohio. An evidentiary hearing was held on October 29, 2024, and we expect an order from the PUCO by the second quarter of 2025, prior to the end of Smart Grid Phase 1.
Subsidiaries [Member] | Forecast [Member]
Public Utilities, General Disclosures [Line Items]
Estimated Smart Grid Phase 2 costs	683
Estimated Smart Grid Phase 2 capital	240.5
Estimated Smart Grid Phase 2 O&M	$ 18.6

Fair Value (Narrative) (Details

Fair Value (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unrealized Gain (Loss) on Investments	$ 0.4	$ (0.2)	$ 0.7	$ 0.2
Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	0.3		0.3		$ 0.6
Level 2 [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	0		0		0
Level 3 [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	0		0		0
Subsidiaries [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Unrealized Gain (Loss) on Investments	0.4	$ (0.2)	0.7	$ 0.2
Subsidiaries [Member] | Level 1 [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	0.3		0.3		0.6
Subsidiaries [Member] | Level 2 [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	0		0		0
Subsidiaries [Member] | Level 3 [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	0		0		0
Estimate of Fair Value Measurement [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	0.3		0.3		0.6
Estimate of Fair Value Measurement [Member] | Subsidiaries [Member] | Money Market Funds [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Investments, Fair Value Disclosure	$ 0.3		$ 0.3		$ 0.6

Fair Value (Fair Value and Cost

Fair Value (Fair Value and Cost of Non-Derivative Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Long-term Debt	$ 1,839.3	$ 1,837.6
Subsidiaries [Member]
Long-term Debt	1,012.8	1,012.5
Money Market Funds [Member] | Fair Value [Member]
Investments, Fair Value Disclosure	0.3	0.6
Money Market Funds [Member] | Fair Value [Member] | Subsidiaries [Member]
Investments, Fair Value Disclosure	$ 0.3	$ 0.6

Fair Value (Fair Value of Asset

Fair Value (Fair Value of Assets and Liabilities Measured on Recurring Basis) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Long-term Debt	$ 1,839.3	$ 1,837.6
Subsidiaries [Member]
Long-term Debt	1,012.8	1,012.5
Level 1 [Member]
Total Assets	8.1	7.8
Level 1 [Member] | Subsidiaries [Member]
Total Assets	8.1	7.8
Level 2 [Member]
Total Assets	0	0
Level 2 [Member] | Subsidiaries [Member]
Total Assets	0	0
Level 3 [Member]
Total Assets	0	0
Level 3 [Member] | Subsidiaries [Member]
Total Assets	0	0
Fair Value [Member]
Total Assets	8.1	7.8
Fair Value [Member] | Subsidiaries [Member]
Total Assets	8.1	7.8
Money Market Funds [Member] | Level 1 [Member]
Investments, Fair Value Disclosure	0.3	0.6
Money Market Funds [Member] | Level 1 [Member] | Subsidiaries [Member]
Investments, Fair Value Disclosure	0.3	0.6
Money Market Funds [Member] | Level 2 [Member]
Investments, Fair Value Disclosure	0	0
Money Market Funds [Member] | Level 2 [Member] | Subsidiaries [Member]
Investments, Fair Value Disclosure	0	0
Money Market Funds [Member] | Level 3 [Member]
Investments, Fair Value Disclosure	0	0
Money Market Funds [Member] | Level 3 [Member] | Subsidiaries [Member]
Investments, Fair Value Disclosure	0	0
Money Market Funds [Member] | Fair Value [Member]
Investments, Fair Value Disclosure	0.3	0.6
Money Market Funds [Member] | Fair Value [Member] | Subsidiaries [Member]
Investments, Fair Value Disclosure	0.3	0.6
Debt [Member] | Level 1 [Member]
Debt	0	0
Debt [Member] | Level 1 [Member] | Subsidiaries [Member]
Debt	0	0
Debt [Member] | Level 2 [Member]
Debt	1,725.2	1,706.2
Debt [Member] | Level 2 [Member] | Subsidiaries [Member]
Debt	918.8	909.9
Debt [Member] | Level 3 [Member]
Debt	16.7	16.8
Debt [Member] | Level 3 [Member] | Subsidiaries [Member]
Debt	16.7	16.8
Debt [Member] | Fair Value [Member]
Debt	1,741.9	1,723
Debt [Member] | Fair Value [Member] | Subsidiaries [Member]
Debt	935.5	926.7
Mutual Fund | Level 1 [Member]
Investments, Fair Value Disclosure	7.8	7.2
Mutual Fund | Level 1 [Member] | Subsidiaries [Member]
Investments, Fair Value Disclosure	7.8	7.2
Mutual Fund | Level 2 [Member]
Investments, Fair Value Disclosure	0	0
Mutual Fund | Level 2 [Member] | Subsidiaries [Member]
Investments, Fair Value Disclosure	0	0
Mutual Fund | Level 3 [Member]
Investments, Fair Value Disclosure	0	0
Mutual Fund | Level 3 [Member] | Subsidiaries [Member]
Investments, Fair Value Disclosure	0	0
Mutual Fund | Fair Value [Member]
Investments, Fair Value Disclosure	7.8	7.2
Mutual Fund | Fair Value [Member] | Subsidiaries [Member]
Investments, Fair Value Disclosure	$ 7.8	$ 7.2

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Jun. 30, 2024	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Derivative [Line Items]
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	$ (0.1)	$ (0.2)	$ (0.6)	$ (0.6)
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	10.6	$ 11.4	10.6	$ 11.4	$ 10.7		$ 11.6	$ 12
Interest Rate Contract [Member]
Derivative [Line Items]
Portion expected to be reclassified to earnings in the next twelve months	$ (0.8)		$ (0.8)
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax						$ 11.2

Derivative Instruments and He_4

Derivative Instruments and Hedging Activities (Gains or Losses Recognized in AOCI for the Cash Flow Hedges) (Details) $ in Millions	Sep. 30, 2024 USD ($)
Interest Rate Contract [Member]
Accumulated Derivative Gain/Loss in AOCI [Roll Forward]
Portion expected to be reclassified to earnings in the next twelve months	$ (0.8)

Debt (Narrative) (Details)

Debt (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Debt Instrument [Line Items]
Proceeds from Issuance of Long-term Debt	$ 0	$ 100
Less: current portion	(414)		$ (0.2)
Debt Instrument, Unamortized Discount (Premium), Net	(0.6)		(0.6)
Short-Term Bank Loans and Notes Payable	150
Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term Line of Credit	45		15
Proceeds from Issuance of Long-term Debt	0	$ 100
Less: current portion	(0.2)		(0.2)
Deferred Finance Costs, Net, Including Acquisition Adjustments	(6.6)		(7.1)
Debt Instrument, Unamortized Discount (Premium), Net	(2.3)		(2.2)
Short-Term Bank Loans and Notes Payable	150
3.95% Senior Notes due 2049 [Member] | Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 425		425
Debt Instrument, Interest Rate, Effective Percentage	3.95%
Revolving Credit Facility [Member] | Subsidiaries [Member]
Debt Instrument [Line Items]
Debt Covenant, Total Debt to Total Capitalization Ratio, Maximum	0.67
3.25% First Mortgage Bonds due 2040 [Member] | Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 140		140
Debt Instrument, Interest Rate, Effective Percentage	3.20%
U.S. Government note maturing in February 2061 - 4.20% [Member] | Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			16.8
Debt instrument interest percentage	4.20%
4.25% Tax-exempt First Mortgage Bonds due 2027 | Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 100		100
Debt Instrument, Interest Rate, Effective Percentage	4.25%
4.00% Tax-exempt First Mortgage Bonds due 2027 | Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 40		$ 40
Debt Instrument, Interest Rate, Effective Percentage	4%

Debt (Long-term Debt) (Details)

Debt (Long-term Debt) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Debt Instrument [Line Items]
Unamortized deferred finance costs	$ (3.5)		$ (4.9)
Unamortized debt discounts	(0.6)		(0.6)
Total long-term debt	1,839.3		1,837.6
Less: current portion	(414)		(0.2)
Long-term debt	1,425.3		1,837.4
Proceeds from Issuance of Long-term Debt	$ 0	$ 100
Long-term Debt	DEBT Long-term debt is as follows: Interest September 30, December 31, $ in millions Rate Due 2024 2023 AES Ohio debt First Mortgage Bonds 3.95 % 2049 $ 425.0 $ 425.0 First Mortgage Bonds 3.20 % 2040 140.0 140.0 First Mortgage Bonds 5.70 % 2033 107.5 107.5 First Mortgage Bonds 5.19 % 2033 100.0 100.0 First Mortgage Bonds 5.49 % 2028 92.5 92.5 Tax-exempt First Mortgage Bonds (a) 4.25 % 2027 100.0 100.0 Tax-exempt First Mortgage Bonds (b) 4.00 % 2027 40.0 40.0 U.S. Government note 4.20 % 2061 16.7 16.8 Unamortized deferred financing costs (6.6) (7.1) Unamortized debt discounts (2.3) (2.2) Total long-term debt at AES Ohio 1,012.8 1,012.5 DPL Inc. debt Senior unsecured notes 4.125 % 2025 415.0 415.0 Senior unsecured notes 4.35 % 2029 400.0 400.0 Note to DPL Capital Trust II (c) 8.125 % 2031 15.6 15.6 Unamortized deferred financing costs (3.5) (4.9) Unamortized debt discounts (0.6) (0.6) Total DPL consolidated long-term debt 1,839.3 1,837.6 Less: current portion (414.0) (0.2) DPL consolidated long-term debt, net of current portion $ 1,425.3 $ 1,837.4 (a) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of November 1, 2040 but are subject to a mandatory put in June 2027. (b) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of January 1, 2034 but are subject to a mandatory put in June 2027. (c) Note payable to related party. Revolving credit agreements As of September 30, 2024 and December 31, 2023, the AES Ohio Credit Agreement had outstanding borrowings of $45.0 million and $15.0 million, respectively. Significant Transactions In August 2024, AES Ohio entered into an unsecured $150.0 million 364-day term loan agreement ("AES Ohio Term Loan"). The AES Ohio Term Loan was fully drawn at closing with the proceeds being used for general corporate purposes. This agreement matures on August 13, 2025, and bears interest at variable rates as described in the $150 million Term Loan Agreement. The AES Ohio Term Loan contains customary representations, warranties and covenants, including a leverage covenant consistent with the leverage covenant contained in AES Ohio's Credit Agreement. AES Ohio has classified the AES Ohio Term Loan as short-term indebtedness as it matures in August 2025. Management plans to repay the AES Ohio Term Loan Agreement through a combination of funds from debt financings and parent equity capital contributions. DPL's Senior unsecured notes DPL has $415.0 million of 4.125% Senior unsecured notes due July 1, 2025 ("2025 DPL Notes"). Although current liquid funds are not sufficient to repay the amounts due under the 2025 DPL Notes at maturity, we will use a portion of the proceeds from the Closings to repay the notes in full (see Note 1. Overview and Summary of Significant Accounting Policies - Agreement to Sell Minority Interest in AES Ohio for more information). Long-term debt covenants and restrictions The AES Ohio Credit Agreement, AES Ohio Term Loan, and Fifty-Third, Fifty-Fourth and Fifty-Fifth Supplemental Indentures to the First Mortgage, pursuant to which the 3.20% Bonds due 2040, the 5.19% Bonds due 2033, the 5.49% Bonds due 2028 and the 5.70% Bonds due 2033 were issued, respectively, each contain one financial covenant. The covenant measures Total Debt to Total Capitalization and is calculated, at the end of each fiscal quarter, by dividing total debt at the end of the quarter by total capitalization at the end of the quarter. AES Ohio’s Total Debt to Total Capitalization ratio shall not be greater than 0.67 to 1.00. As of September 30, 2024, AES Ohio was in compliance with this financial covenant. AES Ohio does not have any meaningful restrictions in its debt financing documents prohibiting dividends and return of capital payments to its parent, DPL. As of September 30, 2024, AES Ohio was in compliance with all debt covenants, including the financial covenant described above. Substantially all property, plant & equipment of AES Ohio is subject to the lien of the mortgage securing AES Ohio’s First and Refunding Mortgage.
Subsidiaries [Member]
Debt Instrument [Line Items]
Unamortized deferred finance costs	$ (6.6)		(7.1)
Unamortized debt discounts	(2.3)		(2.2)
Total long-term debt at subsidiary	1,012.8		1,012.5
Total long-term debt	1,012.8		1,012.5
Less: current portion	(0.2)		(0.2)
Long-term debt	1,012.6		1,012.3
Long-term Line of Credit	45		15
Proceeds from Issuance of Long-term Debt	$ 0	$ 100
Long-term Debt	DEBT Long-term debt is as follows: Interest September 30, December 31, $ in millions Rate Due 2024 2023 First Mortgage Bonds 3.95 % 2049 $ 425.0 $ 425.0 First Mortgage Bonds 3.20 % 2040 140.0 140.0 First Mortgage Bonds 5.70 % 2033 107.5 107.5 First Mortgage Bonds 5.19 % 2033 100.0 100.0 First Mortgage Bonds 5.49 % 2028 92.5 92.5 Tax-exempt First Mortgage Bonds (a) 4.25 % 2027 100.0 100.0 Tax-exempt First Mortgage Bonds (b) 4.00 % 2027 40.0 40.0 U.S. Government note 4.20 % 2061 16.7 16.8 Unamortized deferred financing costs (6.6) (7.1) Unamortized debt discounts (2.3) (2.2) Total long-term debt 1,012.8 1,012.5 Less: current portion (0.2) (0.2) Long-term debt, net of current portion $ 1,012.6 $ 1,012.3 (a) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of November 1, 2040 but are subject to a mandatory put in June 2027. (b) First mortgage bonds issued to the OAQDA, to secure the loan of proceeds from tax-exempt bonds issued by the OAQDA. The bonds have a final maturity date of January 1, 2034 but are subject to a mandatory put in June 2027. Revolving credit agreements As of September 30, 2024 and December 31, 2023, the AES Ohio Credit Agreement had outstanding borrowings of $45.0 million and $15.0 million, respectively. Significant Transactions In August 2024, AES Ohio entered into an unsecured $150.0 million 364-day term loan agreement ("AES Ohio Term Loan"). The AES Ohio Term Loan was fully drawn at closing with the proceeds being used for general corporate purposes. This agreement matures on August 13, 2025, and bears interest at variable rates as described in the $150 million Term Loan Agreement. The AES Ohio Term Loan contains customary representations, warranties and covenants, including a leverage covenant consistent with the leverage covenant contained in AES Ohio's Credit Agreement. AES Ohio has classified the AES Ohio Term Loan as short-term indebtedness as it matures in August 2025. Management plans to repay the AES Ohio Term Loan Agreement through a combination of funds from debt financings and parent equity capital contributions. Long-term debt covenants and restrictions The AES Ohio Credit Agreement, AES Ohio Term Loan, and Fifty-Third, Fifty-Fourth and Fifty-Fifth Supplemental Indentures to the First Mortgage, pursuant to which the 3.20% Bonds due 2040, the 5.19% Bonds due 2033, the 5.49% Bonds due 2028 and the 5.70% Bonds due 2033 were issued, respectively, each contain one financial covenant. The covenant measures Total Debt to Total Capitalization and is calculated, at the end of each fiscal quarter, by dividing total debt at the end of the quarter by total capitalization at the end of the quarter. AES Ohio’s Total Debt to Total Capitalization ratio shall not be greater than 0.67 to 1.00. As of September 30, 2024, AES Ohio was in compliance with this financial covenant. As of September 30, 2024, AES Ohio was in compliance with all debt covenants, including the financial covenant described above. AES Ohio does not have any meaningful restrictions in its debt financing documents prohibiting dividends and return of capital payments to its parent, DPL. Substantially all property, plant & equipment of AES Ohio is subject to the lien of the mortgage securing AES Ohio’s First and Refunding Mortgage.
3.95% Senior Notes due 2049 [Member] | Subsidiaries [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	3.95%
Long-term Debt, Gross	$ 425		425
U.S. Government note maturing in February 2061 - 4.20% [Member] | Subsidiaries [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage	4.20%
Long-term Debt, Gross			16.8
4.35% Senior Notes due 2029 [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage	4.35%
Long-term Debt, Gross	$ 400		400
Note to DPL Capital Trust II Maturing in September 2031 - 8.125% [Member]
Debt Instrument [Line Items]
Debt instrument interest percentage	8.125%
Long-term Debt, Gross	$ 15.6		15.6
4.13% Senior Notes due 2025
Debt Instrument [Line Items]
Debt instrument interest percentage	4.125%
Long-term Debt, Gross	$ 415		415
3.25% First Mortgage Bonds due 2040 [Member] | Subsidiaries [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	3.20%
Long-term Debt, Gross	$ 140		140
4.25% Tax-exempt First Mortgage Bonds due 2027 | Subsidiaries [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	4.25%
Long-term Debt, Gross	$ 100		100
4.00% Tax-exempt First Mortgage Bonds due 2027 | Subsidiaries [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	4%
Long-term Debt, Gross	$ 40		40
5.19% First Mortgage Bonds due 2033 | Subsidiaries [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	5.19%
Long-term Debt, Gross	$ 100		100
5.70% Senior Notes due 2033 | Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	107.5		107.5
5.49% Senior Notes due 2028 | Subsidiaries [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 92.5		$ 92.5
5.70% Tax-exempt First Mortgage Bonds due 2033 | Subsidiaries [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	5.70%
5.49% Tax-exempt First Mortgage Bonds due 2028 | Subsidiaries [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	5.49%

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2024
Entity Information [Line Items]
Estimated annual effective income tax rate					(53.10%)
Effective Income Tax Rate Reconciliation, Including Discontinued Operations, Percent	(267.90%)	19.90%	(24.90%)	13.30%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			22.40%
Effective Income Tax Rate Reconciliation [Line Items]
Estimated annual effective income tax rate					(53.10%)
Subsidiaries [Member]
Entity Information [Line Items]
Effective Income Tax Rate Reconciliation, Including Discontinued Operations, Percent	(17.90%)	20.90%	10.20%	17.60%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent			22.40%

Benefit Plans (Net Periodic Ben

Benefit Plans (Net Periodic Benefit Cost (Income)) (Details) - Pension [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Contributions by employer			$ 7.5	$ 7.5
Service cost	$ 0.7	$ 0.8	1.9	2.2
Interest cost	3.6	3.9	11	11.9
Expected return on assets	(3.7)	(4.4)	(11.1)	(13.2)
Prior service cost	0.2	0.3	0.7	0.8
Actuarial loss / (gain)	0.5	0.2	1.6	0.5
Net periodic benefit cost	1.3	0.8	4.1	2.2
Subsidiaries [Member]
Contributions by employer			7.5	7.5
Service cost	0.7	0.8	1.9	2.2
Interest cost	3.6	3.9	11	11.9
Expected return on assets	(3.7)	(4.4)	(11.1)	(13.2)
Prior service cost	0.3	0.2	0.7	0.8
Actuarial loss / (gain)	0.9	0.3	2.9	0.9
Net periodic benefit cost	$ 1.8	$ 0.8	$ 5.4	$ 2.6

Equity (Details)

Equity (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Sep. 30, 2024	Sep. 30, 2023
Stockholders' Equity Note Disclosure							During the nine months ended September 30, 2024, DPL received $200.0 million in equity contributions from AES. DPL then made the same investment in AES Ohio.
Cash Contribution from Parent Company							$ 200	$ 260
Proceeds from Contributions from Parent	$ 70	$ 130			$ 112		$ 200	239
Non-cash capital contribution	0.1			$ 127
Payment against tax receivable balance from Parent								21
Stockholders' Equity, Other					0.1
Other Additional Capital [Member]
Proceeds from Contributions from Parent	70	130		127	112
Stockholders' Equity, Other	0.1				0.1
Subsidiaries [Member]
Stockholders' Equity Note Disclosure							SHAREHOLDER'S EQUITY During the nine months ended September 30, 2024, DPL made equity contributions of $200.0 million to AES Ohio. During the nine months ended September 30, 2023, DPL made equity contributions of $260.0 million to AES Ohio. The proceeds from these equity contributions allow AES Ohio to seek to improve its infrastructure and modernize its grid while maintaining liquidity.
Proceeds from Contributions from Parent	$ 70	$ 130		135	125		$ 200	$ 260
Stockholders' Equity, Other			$ (0.1)	(0.1)	0.1	$ (0.1)
Subsidiaries [Member] | Other Additional Capital [Member]
Proceeds from Contributions from Parent				135	125
Stockholders' Equity, Other			$ (0.1)	$ 0	$ 0.1	$ 0

Contractual Obligations, Comm_2

Contractual Obligations, Commercial Commitments and Contingencies (Narrative) (Details) - Subsidiaries [Member] $ in Millions	Sep. 30, 2024 USD ($)
Debt Obligation on 4.9% Equity Ownership [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Equity ownership interest	4.90%
Equity ownership interest aggregate cost	$ 49.7
Electric Generation Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Debt obligation	$ 1,000

Business Segments (Narrative) (

Business Segments (Narrative) (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024 USD ($)	Sep. 30, 2023 USD ($)	Sep. 30, 2024 USD ($) mi² customer segment	Sep. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Segment Reporting Information [Line Items]
Total assets	$ 3,200.5		$ 3,200.5		$ 2,906.2
Revenues	227.5	$ 224.2	663.1	$ 666.3
Revenue from external customers
Segment Reporting Information [Line Items]
Revenues	227.5	224.2	663.1	666.3
Intersegment revenue
Segment Reporting Information [Line Items]
Revenues	0	0	$ 0	0
Subsidiaries [Member]
Segment Reporting Information [Line Items]
Number of Operating Segments | segment			1
Approximate number of retail customers | customer			541,000
Service area, square miles | mi²			6,000
Total assets	3,150.2		$ 3,150.2		2,871
Revenues	225.4	222	656.6	659.5
Utility [Member]
Segment Reporting Information [Line Items]
Revenues	225.4	222	656.6	659.5
Corporate and Other
Segment Reporting Information [Line Items]
Revenues	3.6	3.9	10.9	10.5
Operating Segments [Member] | Utility [Member]
Segment Reporting Information [Line Items]
Revenues	225.4	222	656.6	659.5
Operating Segments [Member] | Utility [Member] | Revenue from external customers
Segment Reporting Information [Line Items]
Revenues	225.1	221.8	655.9	659
Operating Segments [Member] | Utility [Member] | Intersegment revenue
Segment Reporting Information [Line Items]
Revenues	0.3	0.2	0.7	0.5
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Total assets	50.3		50.3		$ 35.2
Revenues	3.6	3.9	10.9	10.5
Corporate, Non-Segment [Member] | Revenue from external customers
Segment Reporting Information [Line Items]
Revenues	2.4	2.4	7.2	7.3
Corporate, Non-Segment [Member] | Intersegment revenue
Segment Reporting Information [Line Items]
Revenues	1.2	1.5	3.7	3.2
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	(1.5)	(1.7)	(4.4)	(3.7)
Intersegment Eliminations | Revenue from external customers
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Intersegment Eliminations | Intersegment revenue
Segment Reporting Information [Line Items]
Revenues	$ (1.5)	$ (1.7)	$ (4.4)	$ (3.7)

Business Segments (Segment Fina

Business Segments (Segment Financial Information) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Revenues	$ 227.5	$ 224.2	$ 663.1	$ 666.3
Depreciation and amortization	25.7	20.6	69.4	60.9
Interest expense	21.1	7.8	62.2	45.2
Total assets	3,200.5		3,200.5		$ 2,906.2
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	2.8	48.2	18.5	39.9
Revenue from external customers
Segment Reporting Information [Line Items]
Revenues	227.5	224.2	663.1	666.3
Intersegment revenue
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Utility [Member]
Segment Reporting Information [Line Items]
Revenues	225.4	222	656.6	659.5
Operating Segments [Member] | Utility [Member]
Segment Reporting Information [Line Items]
Revenues	225.4	222	656.6	659.5
Depreciation and amortization	25.2	20.3	68	59.9
Interest expense	11.8	(1.3)	34.7	16.7
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	10.6	55.1	41.2	64.1
Operating Segments [Member] | Utility [Member] | Revenue from external customers
Segment Reporting Information [Line Items]
Revenues	225.1	221.8	655.9	659
Operating Segments [Member] | Utility [Member] | Intersegment revenue
Segment Reporting Information [Line Items]
Revenues	0.3	0.2	0.7	0.5
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Revenues	3.6	3.9	10.9	10.5
Depreciation and amortization	0.5	0.3	1.4	1
Interest expense	9.3	9.1	27.5	28.5
Total assets	50.3		50.3		35.2
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(7.8)	(6.9)	(22.7)	(24.2)
Corporate, Non-Segment [Member] | Revenue from external customers
Segment Reporting Information [Line Items]
Revenues	2.4	2.4	7.2	7.3
Corporate, Non-Segment [Member] | Intersegment revenue
Segment Reporting Information [Line Items]
Revenues	1.2	1.5	3.7	3.2
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues	(1.5)	(1.7)	(4.4)	(3.7)
Depreciation and amortization	0	0	0	0
Interest expense	0	0	0	0
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	0	0	0	0
Intersegment Eliminations | Revenue from external customers
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Intersegment Eliminations | Intersegment revenue
Segment Reporting Information [Line Items]
Revenues	(1.5)	(1.7)	(4.4)	(3.7)
Subsidiaries [Member]
Segment Reporting Information [Line Items]
Revenues	225.4	222	656.6	659.5
Depreciation and amortization	25.2	20.3	68	59.9
Interest expense	11.8	(1.3)	34.7	16.7
Total assets	3,150.2		3,150.2		$ 2,871
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	$ 10.6	$ 55.1	$ 41.2	$ 64.1

Revenue (Details)

Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Revenue from Contract with Customer, Excluding Assessed Tax	$ 224.3	$ 225.8	$ 654.7	$ 668.7
RTO Revenue	27	21.5	89	65.8
RTO Capacity Revenue	0.3	0.7	0.7	3.2
Revenues	227.5	224.2	663.1	666.3
Contract with Customer, Asset, before Allowance for Credit Loss	94.3		94.3		$ 90.4
Subsidiaries [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	222.1	223.6	648.2	661.9
RTO Revenue	27	21.4	89	65.7
RTO Capacity Revenue	0.3	0.7	0.7	3.2
Revenues	225.4	222	656.6	659.5
Contract with Customer, Asset, before Allowance for Credit Loss	93.4		93.4		$ 89.4
Utility [Member]
RTO Revenue	27	21.4	89	65.7
RTO Capacity Revenue	0.3	0.7	0.7	3.2
Revenues	225.4	222	656.6	659.5
Corporate and Other
RTO Revenue	0	0.1	0	0.1
RTO Capacity Revenue	0	0	0	0
Revenues	3.6	3.9	10.9	10.5
Adjustments and Eliminations
RTO Revenue	0	0	0	0
RTO Capacity Revenue	0	0	0	0
Revenues	(1.5)	(1.7)	(4.4)	(3.7)
Other Revenues [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	2.4	2.3	7.2	7.2
Other non-606 revenue	3.2	(1.4)	8.4	(2.2)
Other Revenues [Member] | Subsidiaries [Member]
Other non-606 revenue	3.3	(1.4)	8.4	(2.2)
Other Revenues [Member] | Utility [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Other non-606 revenue	3.3	(1.4)	8.4	(2.2)
Other Revenues [Member] | Corporate and Other
Revenue from Contract with Customer, Excluding Assessed Tax	2.4	2.3	7.2	7.2
Other non-606 revenue	1.2	1.5	3.7	3.2
Other Revenues [Member] | Adjustments and Eliminations
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Other non-606 revenue	(1.3)	(1.5)	(3.7)	(3.2)
Wholesale Revenue [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	4.3	4	11.6	10.8
Wholesale Revenue [Member] | Subsidiaries [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	4.5	4.2	12.3	11.3
Wholesale Revenue [Member] | Utility [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	4.5	4.2	12.3	11.3
Wholesale Revenue [Member] | Corporate and Other
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Wholesale Revenue [Member] | Adjustments and Eliminations
Revenue from Contract with Customer, Excluding Assessed Tax	(0.2)	(0.2)	(0.7)	(0.5)
Retail Revenue [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	190.3	197.3	546.2	581.7
Other non-606 revenue		(0.2)	0	(0.2)
Retail Revenue [Member] | Residential Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	120.9	127.8	347.1	377.9
Retail Revenue [Member] | Commercial Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	41.9	42.7	120.5	124.8
Retail Revenue [Member] | Industrial Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	17.4	16.5	50.1	50.4
Retail Revenue [Member] | Governmental Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	7.4	6.8	19.5	18.7
Retail Revenue [Member] | Other Revenues [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	2.7	3.5	9	9.9
Retail Revenue [Member] | Utility [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	190.3	197.3	546.2	581.7
Other non-606 revenue		(0.2)	0	(0.2)
Retail Revenue [Member] | Utility [Member] | Residential Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	120.9	127.8	347.1	377.9
Retail Revenue [Member] | Utility [Member] | Commercial Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	41.9	42.7	120.5	124.8
Retail Revenue [Member] | Utility [Member] | Industrial Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	17.4	16.5	50.1	50.4
Retail Revenue [Member] | Utility [Member] | Governmental Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	7.4	6.8	19.5	18.7
Retail Revenue [Member] | Utility [Member] | Other Revenues [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	2.7	3.5	9	9.9
Retail Revenue [Member] | Corporate and Other
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Other non-606 revenue		0	0	0
Retail Revenue [Member] | Corporate and Other | Residential Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Retail Revenue [Member] | Corporate and Other | Commercial Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Retail Revenue [Member] | Corporate and Other | Industrial Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Retail Revenue [Member] | Corporate and Other | Governmental Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Retail Revenue [Member] | Corporate and Other | Other Revenues [Member]
Revenue from Contract with Customer, Excluding Assessed Tax	0	0	0	0
Retail Revenue [Member] | Adjustments and Eliminations
Revenue from Contract with Customer, Excluding Assessed Tax			0	0
Other non-606 revenue		0	0	0
Retail Revenue [Member] | Adjustments and Eliminations | Residential Revenue
Revenue from Contract with Customer, Excluding Assessed Tax	$ 0	$ 0	0	0
Retail Revenue [Member] | Adjustments and Eliminations | Commercial Revenue
Revenue from Contract with Customer, Excluding Assessed Tax			0	0
Retail Revenue [Member] | Adjustments and Eliminations | Industrial Revenue
Revenue from Contract with Customer, Excluding Assessed Tax			0	0
Retail Revenue [Member] | Adjustments and Eliminations | Governmental Revenue
Revenue from Contract with Customer, Excluding Assessed Tax			0	0
Retail Revenue [Member] | Adjustments and Eliminations | Other Revenues [Member]
Revenue from Contract with Customer, Excluding Assessed Tax			$ 0	$ 0

Discontinued Operations (Detail

Discontinued Operations (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Payments for (Proceeds from) Removal Costs	$ (21.9)	$ (16)
Subsidiaries [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Payments for (Proceeds from) Removal Costs	$ (21.9)	$ (16)