Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2019

Benefit Plans [Abstract]

Net Periodic Benefit Cost

Components of Net Periodic Benefit Cost

	Pension Benefits
	Three Months Ended
(millions of dollars)	Mar. 31, 2019			Apr. 1, 2018
Service cost	$	1.8		$	2.0
Interest cost		3.5			3.0
Expected return on plan assets		(4.6	)		(4.8	)
Amortization:
Prior service cost		0.1			0.2
Recognized net actuarial loss		2.3			2.7
Net periodic benefit cost	$	3.1		$	3.1

	Other Benefits
	Three Months Ended
(millions of dollars)	Mar. 31, 2019			Apr. 1, 2018
Service cost	$	—		$	0.1
Interest cost		0.1			0.1
Amortization:
Prior service cost		—			(0.3	)
Recognized net actuarial (gain)		(0.2	)		(0.2	)
Net periodic benefit cost	$	(0.1	)	$	(0.3	)