Benefit Plans (Tables)

6 Months Ended

Jun. 28, 2015

Benefit Plans [Abstract]

Components of net periodic benefit cost

Components of Net Periodic Benefit Cost

	Pension Benefits
	Three Months Ended						Six Months Ended
	June 28, 2015			June 29, 2014			June 28, 2015			June 29, 2014
	(millions of dollars)
Service cost	$	2.7		$	2.2		$	5.3		$	4.2
Interest cost		3.9			3.4			7.8			6.5
Expected return on plan assets		(5.0	)		(4.6	)		(10.1	)		(8.9	)
Amortization:
Prior service cost		0.3			0.3			0.6			0.6
Recognized net actuarial loss		3.0			1.7			5.7			3.4
Net periodic benefit cost	$	4.9		$	3.0		$	9.3		$	5.8

	Other Benefits
	Three Months Ended						Six Months Ended
	June 28, 2015			June 29, 2014			June 28, 2015			June 29, 2014
	(millions of dollars)
Service cost	$	0.1		$	0.1		$	0.2		$	0.2
Interest cost		0.1			0.1			0.2			0.2
Amortization:
Prior service cost		(0.7	)		(0.8	)		(1.5	)		(1.6	)
Recognized net actuarial (gain)/loss		(0.1	)		(0.1	)		(0.1	)		(0.1	)
Net periodic benefit cost	$	(0.6	)	$	(0.7	)	$	(1.2	)	$	(1.3	)