Overview and Summary of Significant Accounting Policies Overview and Summary of Significant Accounting Polices (Tables)

12 Months Ended

Dec. 31, 2025

Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]

Schedule of Accounts, Notes, Loans and Financing Receivable

Accounts Receivable and Allowance for Credit Losses

The following table summarizes accounts receivable as of December 31, 2025 and 2024:

	December 31,
$ in millions	2025		2024
Accounts receivable, net
Customer receivables	$	117.3	$	79.8
Unbilled revenue	40.9		24.1
Amounts due from affiliates	1.7		3.0
Other	10.0		6.0
Allowance for credit losses	(8.8)		(6.1)
Total accounts receivable, net	$	161.1	$	106.8

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

Accumulated other comprehensive income / (loss)

The changes in the components of Accumulated other comprehensive income / (loss) during the years ended December 31, 2025 and 2024 are as follows:

$ in millions	Gains / (losses) on cash flow hedges		Change in unfunded pension and other postretirement obligations		Total
Balance at January 1, 2024	$	11.2	$	(15.8)	$	(4.6)
Other comprehensive income before reclassifications	—		—		—
Amounts reclassified from AOCI / (AOCL) to earnings	(0.8)		0.1		(0.7)
Net current period other comprehensive income / (loss)	(0.8)		0.1		(0.7)
Balance at December 31, 2024	10.4		(15.7)		(5.3)
Other comprehensive loss before reclassifications	—		0.7		0.7
Amounts reclassified from AOCI / (AOCL) to earnings	(0.9)		1.0		0.1
Reclassification of AOCI from sale of redeemable stock of subsidiaries	—		2.7		2.7
DPL LLC conversion tax transfer to Parent (Note 1 and Note 7)	7.9		9.6		17.5
Net current period other comprehensive income	7.0		14.0		21.0
Balance at December 31, 2025	$	17.4	$	(1.7)	$	15.7

Accounts Receivable, Allowance for Credit Loss

The following table is a rollforward of our allowance for credit losses related to the accounts receivable balances for the years ended December 31, 2025 and 2024:

	For the years ended December 31,
$ in millions	2025		2024
Allowance for credit losses:
Beginning balance	$	6.1	$	0.9
Current period provision	13.7		8.3
Write-offs charged against allowance	(11.1)		(3.7)
Recoveries collected	0.1		0.6
Ending balance	$	8.8	$	6.1

Schedule of Cash and Cash Equivalents [Table Text Block]

The following table summarizes cash, cash equivalents and restricted cash amounts reported within the Consolidated Balance Sheets that reconcile to the total of such amounts as shown on the Consolidated Statements of Cash Flows:

	December 31,
$ in millions	2025		2024
Cash and cash equivalents	$	82.9	$	54.0
Restricted cash (included in Prepayments and other current assets)	0.1		0.1
Total cash, cash equivalents and restricted cash	$	83.0	$	54.1