Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	$ 1,492.2	$ 1,556.4	$ 1,199.0
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Investment Security Losses, net	1.4	1.0	1.6
Amortization and Accretion of Securities and Unearned Income, net	64.6	95.9	105.0
Provision for Credit Losses	(14.5)	(14.5)	(28.0)
Depreciation on Buildings and Equipment	103.2	108.6	101.2
Amortization of Computer Software	339.1	334.9	309.1
Amortization of Intangibles	16.6	17.4	11.4
Change in Accrued Income Taxes	(70.7)	(130.0)	36.2
Pension Plan Contributions	(6.1)	(74.5)	(14.5)
Deferred Income Tax Provision	34.3	10.5	(76.1)
Change in Receivables	(50.3)	(197.0)	(119.3)
Change in Interest Payable	(23.6)	28.5	10.7
Change in Collateral With Derivative Counterparties, net	1,154.0	(699.6)	486.2
Other Operating Activities, net	(448.2)	729.9	(302.1)
Net Cash Provided by Operating Activities	2,592.0	1,767.5	1,720.4
CASH FLOWS FROM INVESTING ACTIVITIES
Net Change in Federal Funds Sold and Securities Purchased under Agreements to Resell	486.3	105.7	678.9
Change in Interest-Bearing Deposits with Banks	(614.6)	1,073.8	(467.7)
Net Change in Federal Reserve and Other Central Bank Deposits	(3,683.2)	9,679.6	(12,748.7)
Purchases of Debt Securities – Held to Maturity	(14,154.3)	(21,463.1)	(11,955.2)
Proceeds from Maturity and Redemption of Debt Securities – Held to Maturity	16,290.9	20,036.7	9,924.8
Purchases of Debt Securities – Available for Sale	(12,811.0)	(12,596.9)
Purchases of Debt Securities – Available for Sale			(9,780.0)
Proceeds from Sale, Maturity and Redemption of Debt Securities – Available for Sale	11,057.2	8,958.7	10,103.4
Change in Loans and Leases	1,087.9	66.1	1,451.0
Purchases of Buildings and Equipment	(158.0)	(97.6)	(91.6)
Purchases and Development of Computer Software	(441.8)	(408.4)	(381.2)
Change in Client Security Settlement Receivables	821.0	(49.7)	(592.6)
Acquisition of a Business, Net of Cash Received	(10.5)	(104.2)	(188.5)
Bank-Owned Life Insurance Policy Premiums	(1,500.0)	0.0	0.0
Other Investing Activities, net	225.1	(873.6)	25.8
Net Cash (Used in) Provided by Investing Activities	(3,405.0)	4,327.1	(14,021.6)
CASH FLOWS FROM FINANCING ACTIVITIES
Change in Deposits	4,263.6	(6,163.2)	8,523.6
Change in Federal Funds Purchased	2,041.3	(308.1)	(2,081.2)
Change in Securities Sold under Agreements to Repurchase	320.9	(665.2)	360.5
Change in Short-Term Other Borrowings	(1,184.5)	1,860.9	967.7
Proceeds from Senior Notes	498.0	497.9	350.0
Repayments of Senior Notes	0.0	(314.3)	(208.7)
Proceeds from Issuance of Preferred Stock - Series E	392.5	0.0	0.0
Treasury Stock Purchased	(1,100.2)	(924.3)	(523.1)
Net Proceeds from Stock Options	44.0	32.6	108.0
Cash Dividends Paid on Common Stock	(529.7)	(405.4)	(356.8)
Cash Dividends Paid on Preferred Stock	(46.4)	(46.4)	(49.8)
Other Financing Activities, net	(1.0)	1.1	0.1
Net Cash Provided by (Used In) Financing Activities	615.9	(5,818.2)	11,252.7
Effect of Foreign Currency Exchange Rates on Cash	74.7	(212.9)	234.6
Change in Cash and Due from Banks	(122.4)	63.5	(813.9)
Cash and Due from Banks at Beginning of Year	4,581.6	4,518.1	5,332.0
Cash and Due from Banks at End of Year	4,459.2	4,581.6	4,518.1
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Interest Paid	845.5	670.2	328.8
Income Taxes Paid	437.0	493.5	441.2
Transfers from Loans to OREO	3.5	11.4	8.2
Transfers to Leases Held For Sale from Leases	$ 53.6	$ 0.0	$ 0.0