Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2021

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 September 30 were as follows:

	Pension benefits				Other retirement benefits				Total
($ in millions)	2021		2020		2021		2020		2021		2020
Service cost	$	0.1	$	0.4	$	—	$	—	$	0.1	$	0.4
Interest cost	1.6		1.7		—		—		1.6		1.7
Expected return on assets	(2.9)		(2.8)		—		—		(2.9)		(2.8)
Amortization of prior service credit	—		0.1		(0.1)		(0.2)		(0.1)		(0.1)
Recognized actuarial losses (gains)	0.5		0.4		(0.3)		(0.6)		0.2		(0.2)
Settlements	—		1.1		—		—		—		1.1
Net periodic benefit cost	$	(0.7)	$	0.9	$	(0.4)	$	(0.8)	$	(1.1)	$	0.1

	Pension benefits				Other retirement benefits				Total
($ in millions)	2021		2020		2021		2020		2021		2020
U.S. plans	$	(0.9)	$	0.5	$	(0.4)	$	(0.8)	$	(1.3)	$	(0.3)
International plans	0.2		0.4		—		—		0.2		0.4
Net periodic benefit cost	$	(0.7)	$	0.9	$	(0.4)	$	(0.8)	$	(1.1)	$	0.1

The components of net periodic benefit cost for the nine months ended September 30 were as follows:

	Pension benefits				Other retirement benefits				Total
($ in millions)	2021		2020		2021		2020		2021		2020
Service cost	$	0.9	$	1.0	$	—	$	—	$	0.9	$	1.0
Interest cost	4.5		5.5		0.1		0.1		4.6		5.6
Expected return on assets	(9.0)		(8.8)		—		—		(9.0)		(8.8)
Amortization of prior service credit	0.1		0.1		(0.3)		(0.5)		(0.2)		(0.4)
Recognized actuarial losses (gains)	1.5		1.4		(1.2)		(1.4)		0.3		—
Settlements	0.7		3.4		—		—		0.7		3.4
Net periodic benefit cost	$	(1.3)	$	2.6	$	(1.4)	$	(1.8)	$	(2.7)	$	0.8

	Pension benefits				Other retirement benefits				Total
($ in millions)	2021		2020		2021		2020		2021		2020
U.S. plans	$	(2.4)	$	1.5	$	(1.4)	$	(1.8)	$	(3.8)	$	(0.3)
International plans	1.1		1.1		—		—		1.1		1.1
Net periodic benefit cost	$	(1.3)	$	2.6	$	(1.4)	$	(1.8)	$	(2.7)	$	0.8