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