EMPLOYEE BENEFITS (Tables)

3 Months Ended

Mar. 31, 2017

Compensation and Retirement Disclosure [Abstract]

Schedule of the components of net periodic benefit cost

The following tables show the components of net periodic pension and OPEB costs for our benefit plans.

	Pension Costs
	Three Months Ended March 31
(in millions)	2017			2016
Service cost	$	11.7		$	11.3
Interest cost	31.2			33.2
Expected return on plan assets	(49.6		)	(49.0		)
Amortization of prior service cost	0.7			0.9
Amortization of net actuarial loss	21.9			20.5
Net periodic benefit cost	$	15.9		$	16.9

	OPEB Costs
	Three Months Ended March 31
(in millions)	2017			2016
Service cost	$	6.3		$	6.7
Interest cost	8.5			9.2
Expected return on plan assets	(13.7		)	(13.1		)
Amortization of prior service credit	(2.8		)	(2.3		)
Amortization of net actuarial loss	1.5			2.3
Net periodic benefit (credit) cost	$	(0.2	)	$	2.8