Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2022

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, 2022 and 2021 was:

	Three months ended				Nine months ended
	September 30,				September 30,
$ in millions	2022		2021		2022		2021
Service cost	$	1.2	$	1.2	$	3.7	$	3.4
Interest cost	2.4		2.1		7.2		6.1
Expected return on plan assets	(4.0)		(3.8)		(11.9)		(11.2)
Amortization of unrecognized:
Prior service cost	0.3		0.2		0.8		0.6
Actuarial loss	1.4		2.2		4.1		6.8
Net periodic benefit cost	$	1.3	$	1.9	$	3.9	$	5.7

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, 2022 and 2021 was:

	Three months ended				Nine months ended
	September 30,				September 30,
$ in millions	2022		2021		2022		2021
Service cost	$	1.2	$	1.2	$	3.7	$	3.4
Interest cost	2.4		2.1		7.2		6.1
Expected return on plan assets	(4.0)		(3.8)		(11.9)		(11.2)
Amortization of unrecognized:
Prior service cost	0.3		0.2		0.9		0.8
Actuarial loss	2.0		2.9		5.8		8.5
Net periodic benefit cost	$	1.9	$	2.6	$	5.7	$	7.6