Benefit Plans (Tables)

9 Months Ended

Oct. 01, 2017

Benefit Plans [Abstract]

Components of net periodic benefit cost

Components of Net Periodic Benefit Cost

	Pension Benefits
	Three Months Ended						Nine Months Ended
	Oct. 1, 2017			Oct. 2, 2016			Oct. 1, 2017			Oct. 2, 2016
	(millions of dollars)
Service cost	$	1.4		$	1.7		$	5.5		$	6.3
Interest cost		3.0			3.1			9.2			9.8
Expected return on plan assets		(4.5	)		(4.6	)		(13.6	)		(13.9	)
Amortization:
Prior service cost		0.5			0.2			1.7			0.6
Recognized net actuarial loss		2.1			2.5			6.3			7.6
Net periodic benefit cost	$	2.5		$	2.9		$	9.1		$	10.4

	Other Benefits
	Three Months Ended						Nine Months Ended
	Oct. 1, 2017			Oct. 2, 2016			Oct. 1, 2017			Oct. 2, 2016
	(millions of dollars)
Service cost	$	0.1		$	0.1		$	0.2		$	0.3
Interest cost		0.1			0.1			0.2			0.3
Amortization:
Prior service cost		(0.8	)		(0.8	)		(2.3	)		(2.3	)
Recognized net actuarial (gain) loss		(0.1	)		(0.1	)		(0.2	)		(0.2	)
Net periodic benefit cost	$	(0.7	)	$	(0.7	)	$	(2.1	)	$	(1.9	)