Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2023

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Schedule of Components of Net Periodic Benefit Cost

The components of net periodic benefit cost for the three months ended March 31 were as follows:

	Pension benefits				Other retirement benefits				Total
($ in millions)	2023		2022		2023		2022		2023		2022
Service cost	$	0.3	$	0.4	$	—	$	—	$	0.3	$	0.4
Interest cost	0.6		1.6		0.1		—		0.7		1.6
Expected return on assets	(0.3)		(2.2)		—		—		(0.3)		(2.2)
Recognized actuarial losses (gains)	0.1		0.4		(0.5)		(0.4)		(0.4)		—
Settlements	—		0.6		—		—		—		0.6
Net periodic benefit cost	$	0.7	$	0.8	$	(0.4)	$	(0.4)	$	0.3	$	0.4

	Pension benefits				Other retirement benefits				Total
($ in millions)	2023		2022		2023		2022		2023		2022
U.S. plans	$	0.1	$	0.4	$	(0.4)	$	(0.4)	$	(0.3)	$	—
International plans	0.6		0.4		—		—		0.6		0.4
Net periodic benefit cost	$	0.7	$	0.8	$	(0.4)	$	(0.4)	$	0.3	$	0.4