Benefit Plans (Tables)

6 Months Ended

Jun. 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 June 30 were as follows:

	Pension benefits				Other retirement benefits				Total
($ in millions)	2021		2020		2021		2020		2021		2020
Service cost	$	0.4	$	0.3	$	—	$	—	$	0.4	$	0.3
Interest cost	1.5		1.9		—		—		1.5		1.9
Expected return on assets	(3.0)		(3.0)		—		—		(3.0)		(3.0)
Amortization of prior service credit	0.1		—		(0.1)		(0.1)		—		(0.1)
Recognized actuarial losses (gains)	0.5		0.5		(0.4)		(0.4)		0.1		0.1
Settlements	0.1		0.9		—		—		0.1		0.9
Net periodic benefit cost	$	(0.4)	$	0.6	$	(0.5)	$	(0.5)	$	(0.9)	$	0.1

	Pension benefits				Other retirement benefits				Total
($ in millions)	2021		2020		2021		2020		2021		2020
U.S. plans	$	(1.0)	$	0.2	$	(0.5)	$	(0.5)	$	(1.5)	$	(0.3)
International plans	0.6		0.4		—		—		0.6		0.4
Net periodic benefit cost	$	(0.4)	$	0.6	$	(0.5)	$	(0.5)	$	(0.9)	$	0.1

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

	Pension benefits				Other retirement benefits				Total
($ in millions)	2021		2020		2021		2020		2021		2020
Service cost	$	0.8	$	0.6	$	—	$	—	$	0.8	$	0.6
Interest cost	2.9		3.9		0.1		0.1		3.0		4.0
Expected return on assets	(6.1)		(6.0)		—		—		(6.1)		(6.0)
Amortization of prior service credit	0.1		—		(0.2)		(0.3)		(0.1)		(0.3)
Recognized actuarial losses (gains)	1.0		1.0		(0.8)		(0.8)		0.2		0.2
Settlements	0.7		2.3		—		—		0.7		2.3
Net periodic benefit cost	$	(0.6)	$	1.8	$	(0.9)	$	(1.0)	$	(1.5)	$	0.8

	Pension benefits				Other retirement benefits				Total
($ in millions)	2021		2020		2021		2020		2021		2020
U.S. plans	$	(1.6)	$	1.1	$	(0.9)	$	(1.0)	$	(2.5)	$	0.1
International plans	1.0		0.7		—		—		1.0		0.7
Net periodic benefit cost	$	(0.6)	$	1.8	$	(0.9)	$	(1.0)	$	(1.5)	$	0.8