Defined Benefit Pension and Other Postretirement Benefit (OPEB) Plans

We sponsor several defined benefit pension and OPEB plans for our employees, including non-qualified pension plans. We maintain a separate defined benefit plan for eligible employees in our U.K. operation. The U.S. defined benefit pension plans were closed to new entrants and amended to freeze participation and benefit accruals for existing participants effective December 31, 2013. The U.K. defined benefit plan was closed to new entrants effective December 31, 2002 and was amended to freeze participation for existing participants effective June 30, 2014.

Effective August 1, 2016, we amended the retiree medical benefits portion of our OPEB plan to transition a majority of participants to a private exchange for their health insurance coverage. Prior to the plan amendment, participants paid a subsidized premium for their health insurance coverage, but if they elect to continue participation in the plan they will now purchase coverage on a private exchange and will subsequently be reimbursed through a Health Reimbursement Account (HRA) for an amount equivalent to the subsidy that was previously provided. Participants who continue in the plan will receive a one-time subsidy to minimize the initial out-of-pocket cost of purchasing health insurance. The amendment did not materially change the benefit obligation of the plan.

The following table provides the components of the net periodic benefit cost (credit) for the defined benefit pension and OPEB plans.



	Three Months Ended September 30
	Pension Benefits
	U.S. Plans						U.K. Plan						OPEB
	2016			2015			2016			2015			2016			2015
	(in millions of dollars)
Service Cost	$	1.7		$	1.0		$	—		$	—		$	—		$	—
Interest Cost	21.3			20.5			1.7			2.0			1.8			1.7
Expected Return on Plan Assets	(25.7		)	(27.3		)	(2.5		)	(3.1		)	(0.2		)	(0.1		)
Amortization of:
Net Actuarial Loss	4.0			3.0			0.1			—			—			—
Total	$	1.3		$	(2.8	)	$	(0.7	)	$	(1.1	)	$	1.6		$	1.6



	Nine Months Ended September 30
	Pension Benefits
	U.S. Plans						U.K. Plan						OPEB
	2016			2015			2016			2015			2016			2015
	(in millions of dollars)
Service Cost	$	5.2		$	2.9		$	—		$	—		$	—		$	—
Interest Cost	63.9			61.6			5.4			5.9			5.4			5.3
Expected Return on Plan Assets	(77.1		)	(81.7		)	(7.9		)	(9.3		)	(0.5		)	(0.4		)
Amortization of:
Net Actuarial Loss	12.1			8.7			0.1			0.2			—			—
Prior Service Credit	(0.1		)	—			—			—			(0.1		)	(0.1		)
Plan Amendment	—			—			—			—			0.9			—
Total	$	4.0		$	(8.5	)	$	(2.4	)	$	(3.2	)	$	5.7		$	4.8