Benefit Plans (Tables)

6 Months Ended

Jun. 28, 2020

Benefit Plans [Abstract]

Net Periodic Benefit Cost

Components of Net Periodic Benefit Cost

	Pension Benefits
	Three Months Ended						Six Months Ended
(millions of dollars)	Jun. 28, 2020			Jun. 30, 2019			Jun. 28, 2020			Jun. 30, 2019
Service cost	$	2.0		$	1.8		$	3.9		$	3.6
Interest cost		2.9			3.6			5.9			7.1
Expected return on plan assets		(5.2	)		(4.6	)		(10.4	)		(9.2	)
Amortization:
Prior service cost		0.1			0.1			0.2			0.2
Recognized net actuarial loss		2.8			2.3			5.6			4.6
Settlement loss		4.3			—			4.3			—
Net periodic benefit cost	$	6.9		$	3.2		$	9.5		$	6.3

	Other Benefits
	Three Months Ended						Six Months Ended
(millions of dollars)	Jun. 28, 2020			Jun. 30, 2019			Jun. 28, 2020			Jun. 30, 2019
Service cost	$	—		$	0.1		$	0.1		$	0.1
Interest cost		0.1			—			0.1			0.1
Amortization:
Recognized net actuarial (gain) loss		(0.2	)		(0.2	)		(0.4	)		(0.4	)
Net periodic benefit cost	$	(0.1	)	$	(0.1	)	$	(0.2	)	$	(0.2	)