Employee Benefits (Tables)

12 Months Ended

Dec. 31, 2022

Retirement Benefits [Abstract]

Plan Status of U.S. Plan, Non-U.S. Plans and Supplemental Plan

The following tables set forth the status, amounts included in AOCI, and net periodic pension expense of the U.S. Qualified Plan, Non-U.S. Pension Plans, and U.S. Non-Qualified Plan for 2022, 2021, and 2020. Prior service credits for the U.S. Qualified Plan were amortized on a straight-line basis over 11 years and were amortized in full as of December 31, 2022. Prior service costs for the U.S. Non-Qualified Plan were amortized on a straight-line basis over 10 years and were amortized in full as of December 31, 2021.

TABLE 105: EMPLOYEE BENEFIT PLAN STATUS

	U.S. QUALIFIED PLAN						NON-U.S. PENSION PLANS						U.S. NON-QUALIFIED PLAN
($ In Millions)	2022			2021			2022			2021			2022			2021
Accumulated Benefit Obligation	$	963.3		$	1,246.6		$	126.2		$	204.5		$	97.4		$	125.5
Projected Benefit Obligation	$	1,077.7		$	1,401.3		$	129.0		$	210.1		$	113.6		$	147.7
Plan Assets at Fair Value	1,176.8			1,708.9			134.5			198.7			—			—
Funded Status at December 31	$	99.1		$	307.6		$	5.5		$	(11.4)		$	(113.6)		$	(147.7)
Weighted-Average Assumptions:
Discount Rates	5.22		%	3.03		%	3.76		%	1.34		%	5.15		%	2.80		%
Rate of Increase in Compensation Level	5.56			4.97			1.75			1.50			5.56			4.97
Expected Long-Term Rate of Return on Assets	7.25			5.25			3.99			1.79			N/A			N/A

The following tables set forth the postretirement health care plan status and amounts included in AOCI at December 31, 2022 and 2021, the net periodic postretirement benefit cost of the plan for 2022 and 2021, and the change in the accumulated postretirement benefit obligation during 2022 and 2021.

TABLE 112: POSTRETIREMENT HEALTH CARE PLAN STATUS

	DECEMBER 31,
(In Millions)	2022		2021
Accumulated Postretirement Benefit Obligation at Measurement Date:
Retirees and Dependents	$	8.1	$	8.7
Actives Eligible for Benefits	0.7		1.5
Net Postretirement Benefit Obligation	$	8.8	$	10.2

Amount Included in Accumulated Other Comprehensive Income

	U.S. QUALIFIED PLAN				NON-U.S. PENSION PLANS				U.S. NON-QUALIFIED PLAN
(In Millions)	2022		2021		2022		2021		2022		2021
Net Actuarial Loss	$	418.3	$	273.8	$	24.3	$	40.4	$	59.2	$	86.6
Prior Service (Credit) Cost	—		(0.1)		0.2		0.6		—		—
Gross Amount in Accumulated Other Comprehensive Income	418.3		273.7		24.5		41.0		59.2		86.6
Income Tax Effect	105.1		68.7		4.9		5.2		14.8		21.7
Net Amount in Accumulated Other Comprehensive Income	$	313.2	$	205.0	$	19.6	$	35.8	$	44.4	$	64.9

	DECEMBER 31,
(In Millions)	2022		2021
Net Actuarial (Gain) Loss	$	(5.6)	$	(5.3)
Prior Service (Credit) Cost	(10.6)		(11.5)
Gross Amount in Accumulated Other Comprehensive Income	(16.2)		(16.8)
Income Tax Effect	(4.1)		(4.2)
Net Amount in Accumulated Other Comprehensive Income	$	(12.1)	$	(12.6)

Components of Company's Net Periodic Benefit Cost

	U.S. QUALIFIED PLAN(1)													NON-U.S. PENSION PLANS									U.S. NON-QUALIFIED PLAN
($ In Millions)	2022					2021					2020			2022			2021			2020			2022			2021			2020
Service Cost	$	48.0				$	52.3				$	47.4		$	1.7		$	2.2		$	1.9		$	5.6		$	5.3		$	4.6
Interest Cost	46.3					40.4					43.3			2.5			2.2			2.9			3.9			3.7			4.8
Expected Return on Plan Assets	(85.7)					(79.0)					(76.8)			(3.2)			(3.2)			(3.1)			—			—			—
Amortization:
Net Actuarial Loss	11.4					32.4					35.0			0.6			1.0			0.8			7.4			8.2			7.0
Prior Service (Credit) Cost	(0.1)					(0.4)					(0.4)			—			0.2			0.4			—			0.1			0.2
Net Periodic Pension Expense	$	19.9				$	45.7				$	48.5		$	1.6		$	2.4		$	2.9		$	16.9		$	17.3		$	16.6
Settlement Expense	44.1					27.9					—			0.8			0.4			0.8			—			—			—
Total Pension Expense	$	64.0				$	73.6				$	48.5		$	2.4		$	2.8		$	3.7		$	16.9		$	17.3		$	16.6
Weighted-Average Assumptions:
Discount Rates	3.03		%	4.81	%	2.75		%	3.05	%	3.37		%	1.34		%	0.93		%	1.40		%	2.80		%	2.45		%	3.37		%
	5.49		%	5.22	%	3.06		%	3.03	%
Rate of Increase in Compensation Level				4.97		4.97					4.97			1.50			1.50			1.50			4.97			4.97			4.97
Expected Long-Term Rate of Return on Assets	5.25			6.00		5.25			5.00		5.25			1.79			1.28			1.72			N/A			N/A			N/A
				6.50

(1) In determining the pension expense for the U.S. Qualified Plan for 2022, Northern Trust utilized a discount rate of 3.03% as of December 31, 2021, 4.81% as of June 30, 2022, 5.49% as of September 30, 2022, and 5.22% as of December 31, 2022 and the expected long-term rate of return was 5.25% as of December 31, 2021, 6.00% as of June 30, 2022, and 6.50% as of September 30, 2022.

In determining the pension expense for the U.S. Qualified Plan for 2021, Northern Trust utilized a discount rate of 2.75% as of December 31, 2020, 3.05% as of June 30, 2021, 3.06% as of September 30, 2021, and 3.03% as of December 31, 2021 and an expected long-term rate of return of 5.25% as of both December 31, 2020 and June 30, 2021, and 5.00% as of September 30, 2021.

	FOR THE YEAR ENDED DECEMBER 31,
(In Millions)	2022		2021		2020
Service Cost	$	—	$	—	$	—
Interest Cost	0.3		0.3		0.7
Expected Return on Plan Assets	—		—		—
Amortization
Net Actuarial (Gain) Loss	(0.3)		(0.2)		(0.6)
Prior Service (Credit) Cost	(0.9)		(0.9)		(0.3)
Net Periodic Postretirement Expense	$	(0.9)	$	(0.8)	$	(0.2)

Change in Benefit Obligation, Postretirement Health Care, and in Accumulated Postretirement Benefit Obligation

	U.S. QUALIFIED PLAN				NON-U.S. PENSION PLANS				U.S. NON-QUALIFIED PLAN
(In Millions)	2022		2021		2022		2021		2022		2021
Beginning Balance	$	1,401.3	$	1,470.6	$	210.1	$	236.1	$	147.7	$	162.3
Service Cost	48.0		52.3		1.7		2.2		5.6		5.3
Interest Cost	46.3		40.4		2.5		2.2		3.9		3.7
Employee Contributions	—		—		0.7		0.6		—		—
Plan Amendment	—		—		(0.3)		(1.4)		—		—
Actuarial Loss (Gain)	(281.2)		(19.1)		(64.3)		(10.4)		(20.0)		(2.0)
Settlements	(125.0)		(132.1)		(0.9)		(9.4)		—		—
Benefits Paid	(11.7)		(10.8)		(4.6)		(5.5)		(23.6)		(21.6)
Foreign Exchange Rate Changes	—		—		(15.9)		(4.3)		—		—
Ending Balance	$	1,077.7	$	1,401.3	$	129.0	$	210.1	$	113.6	$	147.7

	FOR THE YEAR ENDED DECEMBER 31,
(In Millions)	2022		2021
Beginning Balance	$	10.2	$	15.7
Service Cost	—		—
Interest Cost	0.3		0.3
Plan Amendment	—		—
Actuarial (Gain) Loss	1.6		(3.3)
Net Claims Paid	(3.3)		(2.5)
Ending Balance	$	8.8	$	10.2

Estimated Future Benefit Payments

(In Millions)	U.S. QUALIFIED PLAN		NON-U.S.PENSION PLANS		U.S. NON-QUALIFIED PLAN
2023	$	90.7	$	4.2	$	20.2
2024	90.7		4.4		13.6
2025	93.9		4.3		14.1
2026	93.5		5.2		11.6
2027	95.3		6.4		12.2
2028-2032	464.7		33.6		54.4

(In Millions)	TOTAL POSTRETIREMENT MEDICAL BENEFITS
2023	$	1.2
2024	1.1
2025	1.1
2026	1.0
2027	0.9
2028-2032	3.8

Change in Plan Assets

	U.S. QUALIFIED PLAN				NON-U.S PENSION PLANS
(In Millions)	2022		2021		2022		2021
Fair Value of Assets at Beginning of Period	$	1,708.9	$	1,793.7	$	198.7	$	211.5
Actual Return on Assets(1)	(395.4)		58.1		(46.9)		(0.8)
Employer Contributions	—		—		3.6		4.5
Employee Contributions	—		—		0.7		0.6
Settlements	(125.0)		(132.1)		(0.9)		(9.4)
Benefits Paid	(11.7)		(10.8)		(4.6)		(5.5)
Foreign Exchange Rate Changes	—		—		(16.1)		(2.2)
Fair Value of Assets at End of Period	$	1,176.8	$	1,708.9	$	134.5	$	198.7

(1) The 2021 actual return on assets for the U.S. Qualified Plan includes a reimbursement of $0.1 million of historical investment expenses paid from the pension trust.

Fair Values of U.S. Pension Plan Assets by Major Asset Category, and their Level within Fair Value Hierarchy

The following table presents the fair values of Northern Trust’s U.S. Qualified Plan assets, by major asset category, and their level within the fair value hierarchy defined by GAAP as of December 31, 2022 and 2021.

TABLE 111: FAIR VALUE OF U.S. QUALIFIED PLAN ASSETS

	DECEMBER 31, 2022
(In Millions)	LEVEL 1		LEVEL 2		LEVEL 3		TOTAL
Domestic Common Stock	$	14.7	$	—	$	—	$	14.7
Foreign Common Stock	0.5		—		—		0.5
Domestic Corporate Bonds	—		263.6		—		263.6
Foreign Corporate Bonds	—		39.6		—		39.6
U.S. Government Obligations	—		77.5		—		77.5
Non-U.S. Government Obligations	—		13.8		—		13.8
Domestic Municipal and Provincial Bonds	—		16.8		—		16.8
Foreign Municipal and Provincial Bonds	—		0.2		—		0.2
Collective Trust Funds	—		522.3		—		522.3
Mutual Funds	61.4		—		—		61.4
Cash and Other(1)	(1.1)		—		—		(1.1)
Total Assets at Fair Value in the Fair Value Hierarchy	$	75.5	$	933.8	$	—	$	1,009.3
Assets Valued at NAV per share
Northern Trust Private Equity Funds							33.2
Northern Trust Hedge Fund							35.2
Real Estate Funds							99.1
Total Assets at Fair Value							$	1,176.8

(1) Negative balance in Cash and Other as of December 31, 2022 primarily relates to due to broker for securities purchased.

	DECEMBER 31, 2021
(In Millions)	LEVEL 1		LEVEL 2		LEVEL 3		TOTAL
Domestic Common Stock	$	17.5	$	—	$	—	$	17.5
Foreign Common Stock	0.3		—		—		0.3
Domestic Corporate Bonds	—		341.7		—		341.7
Foreign Corporate Bonds	—		60.9		—		60.9
U.S. Government Obligations	—		103.9		—		103.9
Non-U.S. Government Obligations	—		20.0		—		20.0
Domestic Municipal and Provincial Bonds	—		21.0		—		21.0
Foreign Municipal and Provincial Bonds	—		0.3		—		0.3
Collective Trust Funds	—		875.3		—		875.3
Mutual Funds	108.9		—		—		108.9
Cash and Other	8.6		—		—		8.6
Total Assets at Fair Value in the Fair Value Hierarchy	$	135.3	$	1,423.1	$	—	$	1,558.4
Assets Valued at NAV per share
Northern Trust Private Equity Funds							34.5
Northern Trust Hedge Fund							36.7
Real Estate Funds							79.3
Total Assets at Fair Value							$	1,708.9

Changes in Level 3 U.S. Pension Plan Assets