Consolidated Statements of Income - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Noninterest Income
Trust, Investment and Other Servicing Fees	$ 3,434,300,000	$ 3,108,100,000	$ 2,980,500,000
Foreign Exchange Trading Income	209,900,000	236,600,000	261,800,000
Treasury Management Fees	56,400,000	62,800,000	64,700,000
Security Commissions and Trading Income	89,600,000	81,400,000	78,700,000
Other Operating Income	157,500,000	241,200,000	247,100,000
Investment Security Losses, net	(1,600,000)	(3,200,000)	(300,000)
Total Noninterest Income	3,946,100,000	3,726,900,000	3,632,500,000
Net Interest Income
Interest Income	1,769,400,000	1,416,900,000	1,224,000,000
Interest Expense	340,200,000	182,000,000	153,900,000
Net Interest Income	1,429,200,000	1,234,900,000	1,070,100,000
Provision for Credit Losses	(28,000,000)	(26,000,000)	(43,000,000)
Net Interest Income after Provision for Credit Losses	1,457,200,000	1,260,900,000	1,113,100,000
Noninterest Expense
Compensation	1,733,700,000	1,541,100,000	1,443,300,000
Employee Benefits	319,900,000	293,300,000	285,300,000
Outside Services	668,400,000	627,100,000	595,700,000
Equipment and Software	524,000,000	467,400,000	454,800,000
Occupancy	191,800,000	177,400,000	173,500,000
Other Operating Expense	331,600,000	364,400,000	328,000,000
Total Noninterest Expense	3,769,400,000	3,470,700,000	3,280,600,000
Income before Income Taxes	1,633,900,000	1,517,100,000	1,465,000,000
Provision for Income Taxes	434,900,000	484,600,000	491,200,000
NET INCOME	1,199,000,000	1,032,500,000	973,800,000
Preferred Stock Dividends	49,800,000	23,400,000	23,400,000
Net Income Applicable to Common Stock	$ 1,149,200,000	$ 1,009,100,000	$ 950,400,000
PER COMMON SHARE
Net Income - Basic (in dollars per share)	$ 4.95	$ 4.35	$ 4.03
Net Income - Diluted (in dollars per share)	$ 4.92	$ 4.32	$ 3.99
Average Number of Common Shares Outstanding - Basic	228,257,664	227,580,584	232,279,849
Average Number of Common Shares Outstanding - Diluted	229,654,401	229,151,406	234,221,729
Note: Changes in Other-Than-Temporary-Impairment (OTTI) Losses	$ (200,000)	$ (3,700,000)	$ 0
Other Security Gains/(Losses), net	(1,400,000)	500,000	(300,000)
Investment Security Losses, net	$ (1,600,000)	$ (3,200,000)	$ (300,000)