Pension and Postretirement Health Care (Tables)

6 Months Ended

Jun. 30, 2016

Compensation and Retirement Disclosure [Abstract]

Components of Company's Net Periodic Benefit Cost

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 and six months ended June 30, 2016 and 2015.

Table 57: Net Periodic Pension Expense (Benefit)

Net Periodic Pension Expense U.S. Plan	Three Months Ended June 30,						Six Months Ended June 30,
(In Millions)	2016			2015			2016			2015
Service Cost	$	9.4		$	9.4		$	18.7		$	18.9
Interest Cost	11.4			11.2			22.9			22.4
Expected Return on Plan Assets	(23.6		)	(24.1		)	(47.2		)	(48.2		)
Amortization
Net Actuarial Loss	4.7			7.4			9.4			14.8
Prior Service Cost	(0.1		)	(0.1		)	(0.2		)	(0.2		)
Net Periodic Pension Expense	$	1.8		$	3.8		$	3.6		$	7.7

Net Periodic Pension Expense Non-U.S. Plans	Three Months Ended June 30,						Six Months Ended June 30,
(In Millions)	2016			2015			2016			2015
Interest Cost	$	1.2		$	1.4		$	2.5		$	2.8
Expected Return on Plan Assets	(1.2		)	(1.4		)	(2.5		)	(2.9		)
Net Actuarial Loss Amortization	0.3			0.4			0.6			0.8
Net Periodic Pension Expense	$	0.3		$	0.4		$	0.6		$	0.7

Net Periodic Pension Expense Supplemental Plan	Three Months Ended June 30,				Six Months Ended June 30,
(In Millions)	2016		2015		2016		2015
Service Cost	$	0.8	$	0.9	$	1.7	$	1.8
Interest Cost	1.3		1.2		2.6		2.5
Amortization
Net Actuarial Loss	1.4		1.9		2.9		3.7
Prior Service Cost	0.1		0.1		0.1		0.1
Net Periodic Pension Expense	$	3.6	$	4.1	$	7.3	$	8.1

Net Periodic Postretirement Expense Postretirement Health Care Plan	Three Months Ended June 30,				Six Months Ended June 30,
(In Millions)	2016		2015		2016		2015
Service Cost	$	0.1	$	0.1	$	0.1	$	0.1
Interest Cost	0.3		0.4		0.7		0.7
Amortization
Net Actuarial (Gain)	—		—		—		—
Net Periodic Postretirement Expense	$	0.4	$	0.5	$	0.8	$	0.8