Regulatory Capital Requirements (Tables)

12 Months Ended

Dec. 31, 2022

Regulatory Capital Requirements Abstract [Abstract]

Risk-Based Capital Amounts and Ratios for Northern Trust on Consolidated Basis and for Bank

The following table provides capital ratios for the Corporation and the Bank determined by Basel III phased in requirements.

TABLE 137: RISK-BASED AND LEVERAGE CAPITAL AMOUNTS AND RATIOS

	DECEMBER 31, 2022								DECEMBER 31, 2021
($ In Millions)	STANDARDIZED APPROACH				ADVANCED APPROACH				STANDARDIZED APPROACH				ADVANCED APPROACH
	BALANCE		RATIO		BALANCE		RATIO		BALANCE		RATIO		BALANCE		RATIO
Common Equity Tier 1 Capital
Northern Trust Corporation	$	9,539.7	10.8	%	$	9,539.7	11.5	%	$	10,277.1	11.9	%	$	10,277.1	13.2	%
The Northern Trust Company	10,111.2		11.6		10,111.2		12.4		10,315.7		12.0		10,315.7		13.5
Minimum to qualify as well-capitalized:
Northern Trust Corporation	N/A		N/A		N/A		N/A		N/A		N/A		N/A		N/A
The Northern Trust Company	5,684.4		6.5		5,286.2		6.5		5,578.7		6.5		4,964.5		6.5
Tier 1 Capital
Northern Trust Corporation	10,397.4		11.8		10,397.4		12.5		11,142.2		12.9		11,142.2		14.3
The Northern Trust Company	10,111.2		11.6		10,111.2		12.4		10,315.7		12.0		10,315.7		13.5
Minimum to qualify as well-capitalized:
Northern Trust Corporation	5,286.5		6.0		4,990.9		6.0		5,177.6		6.0		4,668.4		6.0
The Northern Trust Company	6,996.2		8.0		6,506.1		8.0		6,866.1		8.0		6,110.2		8.0
Total Capital
Northern Trust Corporation	12,245.5		13.9		12,045.9		14.5		12,126.8		14.1		11,942.0		15.3
The Northern Trust Company	11,766.8		13.5		11,567.2		14.2		11,158.4		13.0		10,973.7		14.4
Minimum to qualify as well-capitalized:
Northern Trust Corporation	8,810.8		10.0		8,318.1		10.0		8,629.3		10.0		7,780.7		10.0
The Northern Trust Company	8,745.3		10.0		8,132.6		10.0		8,582.6		10.0		7,637.8		10.0
Tier 1 Leverage
Northern Trust Corporation	10,397.4		7.1		10,397.4		7.1		11,142.2		6.9		11,142.2		6.9
The Northern Trust Company	10,111.2		6.9		10,111.2		6.9		10,315.7		6.4		10,315.7		6.4
Minimum to qualify as well-capitalized:
Northern Trust Corporation	N/A		N/A		N/A		N/A		N/A		N/A		N/A		N/A
The Northern Trust Company	7,323.8		5.0		7,323.8		5.0		8,019.5		5.0		8,019.5		5.0
Supplementary Leverage(1)
Northern Trust Corporation	N/A		N/A		10,397.4		7.9		N/A		N/A		11,142.2		8.2
The Northern Trust Company	N/A		N/A		10,111.2		7.7		N/A		N/A		10,315.7		7.6
Minimum to qualify as well-capitalized:
Northern Trust Corporation	N/A		N/A		N/A		N/A		N/A		N/A		N/A		N/A
The Northern Trust Company	N/A		N/A		3,931.5		3.0		N/A		N/A		4,081.7		3.0

(1) In November 2019, the Federal Reserve Board and other U.S. federal banking agencies adopted a final rule that established a deduction for central bank deposits from the total leverage exposures of custodial banking organizations, including the Corporation and the Bank, equal to the lesser of (i) the total amount of funds the custodial banking organization and its consolidated subsidiaries have on deposit at qualifying central banks and (ii) the total amount of client funds on deposit at the custodial banking organization that are linked to fiduciary or custodial and safekeeping accounts. The rule became effective on April 1, 2020.

The supplementary leverage ratios at December 31, 2022 and December 31, 2021 for the Corporation and the Bank reflect the impact of the final rule.