Regulatory Capital Requirements (Tables)

12 Months Ended

Dec. 31, 2016

Banking and Thrift [Abstract]

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

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

TABLE 127: RISK-BASED CAPITAL AMOUNTS AND RATIOS

	December 31, 2016								December 31, 2015
($ In Millions)	ADVANCED APPROACH				STANDARDIZED APPROACH(1)				ADVANCED APPROACH				STANDARDIZED APPROACH(1)
	BALANCE		RATIO		BALANCE		RATIO		BALANCE		RATIO		BALANCE		RATIO
Common Equity Tier 1
Northern Trust Corporation	$	8,480.4	12.4	%	$	8,480.4	11.8	%	$	8,012.6	11.9	%	$	8,012.6	10.8	%
The Northern Trust Company	8,201.4		12.4		8,201.4		11.5		7,591.7		11.6		7,591.7		10.4
Minimum to qualify as well-capitalized
Northern Trust Corporation	4,436.7		6.5		4,681.4		6.5		4,376.7		6.5		4,807.6		6.5
The Northern Trust Company	4,296.2		6.5		4,624.8		6.5		4,245.5		6.5		4,755.9		6.5
Tier 1
Northern Trust Corporation	9,319.9		13.7		9,319.9		12.9		8,431.3		12.5		8,431.3		11.4
The Northern Trust Company	8,201.4		12.4		8,201.4		11.5		7,591.7		11.6		7,591.7		10.4
Minimum to qualify as well-capitalized:
Northern Trust Corporation	5,460.6		8.0		5,761.7		8.0		5,386.8		8.0		5,917.0		8.0
The Northern Trust Company	5,287.6		8.0		5,692.1		8.0		5,225.2		8.0		5,853.4		8.0
Total
Northern Trust Corporation	10,281.6		15.1		10,475.0		14.5		9,529.7		14.2		9,767.7		13.2
The Northern Trust Company	9,271.4		14.0		9,463.4		13.3		8,538.1		13.1		8,771.4		12.0
Minimum to qualify as well-capitalized:
Northern Trust Corporation	6,825.8		10.0		7,202.1		10.0		6,733.5		10.0		7,396.3		10.0
The Northern Trust Company	6,609.5		10.0		7,115.1		10.0		6,531.5		10.0		7,316.8		10.0
Tier 1 Leverage
Northern Trust Corporation	9,319.9		8.0		9,319.9		8.0		8,431.3		7.5		8,431.3		7.5
The Northern Trust Company	8,201.4		7.0		8,201.4		7.0		7,591.7		6.7		7,591.7		6.7
Minimum to qualify as well-capitalized:
Northern Trust Corporation	5,847.9		5.0		5,847.9		5.0		5,655.0		5.0		5,655.0		5.0
The Northern Trust Company	5,831.0		5.0		5,831.0		5.0		5,639.0		5.0		5,639.0		5.0
Supplementary Leverage(2)
Northern Trust Corporation	9,319.9		6.8		N/A		N/A		8,431.3		6.2		N/A		N/A
The Northern Trust Company	8,201.4		6.0		N/A		N/A		7,591.7		5.6		N/A		N/A
Minimum to qualify as well-capitalized:
Northern Trust Corporation	4,129.9		N/A		N/A		N/A		4,085.0		N/A		N/A		N/A
The Northern Trust Company	4,120.0		N/A		N/A		N/A		4,075.3		N/A		N/A		N/A

(1) Effective with the first quarter of 2015, risk-weighted assets are calculated in accordance with the Basel III Standardized Approach final rules.

(2) Beginning with the first quarter of 2015, advanced approaches banking organizations must calculate and report their supplementary leverage ratio. Effective January 1, 2018, the Corporation will be subject to a minimum supplementary leverage ratio of 3 percent.