Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES
Net Income	$ 2,031.1	$ 1,107.3	$ 1,336.0
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Investment Security Losses, net	189.3	169.5	1.1
Amortization and Accretion of Securities and Unearned Income, net	(35.1)	3.0	59.2
Provision for Credit Losses	(3.0)	24.5	12.0
Depreciation and Amortization	716.8	634.6	553.6
Change in Accrued Income Taxes	183.5	(44.4)	61.3
Pension Plan Contributions	(212.0)	(20.4)	(24.3)
Deferred Income Tax Provision	20.7	(48.2)	(142.7)
Change in Receivables	(6.1)	12.0	57.9
Change in Interest Payable	(41.9)	85.8	172.6
Change in Collateral With Derivative Counterparties, net	(3,287.7)	(72.6)	639.4
Other Operating Activities, net	(41.6)	774.5	(333.7)
Net Cash (Used in) Provided by Operating Activities	(486.0)	2,625.6	2,392.4
CASH FLOWS FROM INVESTING ACTIVITIES
Change in Federal Funds Sold	(25.0)	32.0	(32.0)
Change in Securities Purchased under Agreements to Resell	301.6	285.4	(419.0)
Change in Interest-Bearing Deposits with Banks	(121.0)	28.5	(158.9)
Net Change in Federal Reserve and Other Central Bank Deposits	(5,255.3)	6,205.9	23,483.8
Purchases of Held to Maturity Debt Securities	(26,524.6)	(32,773.9)	(32,830.8)
Proceeds from the Maturity and Redemption of Held to Maturity Debt Securities	30,073.9	32,123.0	37,667.8
Purchases of Available for Sale Debt Securities	(13,010.0)	(7,320.2)	(4,567.7)
Proceeds from Maturity and Redemption of Available for Sale Debt Securities	6,983.0	11,614.8	6,513.0
Change in Loans	4,165.7	(4,702.1)	(2,441.6)
Purchases of Buildings and Equipment	(101.5)	(116.5)	(128.6)
Purchases and Development of Computer Software	(644.0)	(559.3)	(594.9)
Change in Client Security Settlement Receivables	159.9	1,505.5	258.0
Bank-Owned Life Insurance Policy Premiums	0.0	0.0	(500.0)
Proceeds from the sale of Visa Shares	800.6	0.0	0.0
Other Investing Activities, net	633.2	(1,539.0)	(319.3)
Net Cash Provided by (Used in) Investing Activities	(2,563.5)	4,784.1	25,929.8
CASH FLOWS FROM FINANCING ACTIVITIES
Change in Deposits	6,330.8	(8,478.4)	(32,996.9)
Change in Federal Funds Purchased	(885.9)	1,148.6	1,896.7
Change in Securities Sold under Agreements to Repurchase	(322.7)	217.5	35.3
Change in Short-Term Other Borrowings	(103.8)	(1,059.1)	3,966.9
Proceeds from Long-Term Debt	0.0	2,000.0	0.0
Proceeds from Senior Notes	0.0	0.0	1,988.8
Repayments of Senior Notes	0.0	0.0	(500.0)
Treasury Stock Purchased	(937.8)	(347.5)	(35.4)
Net Proceeds from Stock Options	9.4	2.3	3.9
Cash Dividends Paid on Common Stock	(602.3)	(621.5)	(750.2)
Cash Dividends Paid on Preferred Stock	(41.8)	(41.8)	(46.5)
Other Financing Activities, net	(6.4)	(2.7)	0.0
Net Cash Provided by (Used in) Financing Activities	3,439.5	(7,182.6)	(26,437.4)
Effect of Foreign Currency Exchange Rates on Cash	(504.3)	(89.8)	(287.4)
Change in Cash and Due from Banks	(114.3)	137.3	1,597.4
Cash and Due from Banks at Beginning of Period	4,791.5	4,654.2	3,056.8
Cash and Due from Banks at End of Period	4,677.2	4,791.5	4,654.2
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Interest Paid	7,610.3	5,285.5	822.4
Income Taxes Paid	268.6	362.5	459.9
Transfers from Loans to OREO	0.0	0.2	0.0
Transfers from Available for Sale Debt Securities to Held to Maturity Debt Securities	0.0	0.0	6,623.3
Reclassification of certain cash collateral received from Other Operating Activities to Deposits	$ 1,157.2	$ 0.0	$ 0.0