Pension and Postretirement Health Care (Tables)

3 Months Ended

Mar. 31, 2018

Retirement Benefits [Abstract]

Net Periodic Pension Expense (Benefit)

The following tables set forth the net periodic pension and postretirement benefit expense for Northern Trust’s U.S. and non-U.S. pension plans, supplemental pension plan, and postretirement health care plan for the three months ended March 31, 2018 and 2017.

Table 61: Net Periodic Pension Expense (Benefit)

Net Periodic Pension Expense U.S. Plan	Three Months Ended March 31,
(In Millions)	2018			2017
Service Cost	$	10.4		$	9.6
Interest Cost	11.1			11.5
Expected Return on Plan Assets	(22.0		)	(23.5		)
Amortization
Net Actuarial Loss	7.1			4.8
Prior Service Cost	(0.1		)	(0.1		)
Net Periodic Pension Expense	$	6.5		$	2.3

Net Periodic Pension Expense Non-U.S. Plans	Three Months Ended March 31,
(In Millions)	2018			2017
Service Cost	$	0.4		$	—
Interest Cost	1.0			0.9
Expected Return on Plan Assets	(1.1		)	(1.1		)
Net Actuarial Loss Amortization	0.3			0.3
Net Periodic Pension Expense	$	0.6		$	0.1

Net Periodic Pension Expense Supplemental Plan	Three Months Ended March 31,
(In Millions)	2018		2017
Service Cost	$	1.1	$	0.9
Interest Cost	1.3		1.3
Net Actuarial Loss Amortization	1.8		1.4
Net Periodic Pension Expense	$	4.2	$	3.6

Net Periodic Postretirement Expense Postretirement Health Care Plan	Three Months Ended March 31,
(In Millions)	2018		2017
Interest Cost	$	0.3	$	0.4
Net Periodic Postretirement Expense	$	0.3	$	0.4