Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2019

Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]

Schedule of Net Benefit (Credits) Costs [Table Text Block]

The components of net periodic benefit cost (credit) are as follows:

	Pension Benefits
	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2019			2018			2019			2018
	(in millions)
Service cost	$	0.4		$	1.0		$	0.7		$	2.1
Interest cost	7.1			6.8			14.2			13.7
Expected asset return	(10.3		)	(11.5		)	(20.6		)	(23.0		)
Amortized loss	1.5			2.2			3.2			4.4
Amortized prior service cost	—			0.1			—			0.1
Curtailment	—			—			—			3.2
Net periodic benefit cost (credit)	$	(1.3	)	$	(1.4	)	$	(2.5	)	$	0.5
	Other Postretirement Benefits
	Three Months Ended						Six Months Ended
	June 30,						June 30,
	2019			2018			2019			2018
	(in millions)
Service cost	$	0.1		$	0.1		$	0.2		$	0.2
Interest cost	3.2			3.1			6.4			6.2
Amortized loss	—			0.2			0.1			0.4
Amortized prior service credit	(0.4		)	(0.6		)	(0.8		)	(1.3		)
Net periodic benefit cost	$	2.9		$	2.8		$	5.9		$	5.5