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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
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Loans and Leases - Schedule of Loans by Portfolio Segment (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025	Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 64,377	$ 64,156
Allowance for loan and lease losses	(730)	(738)	$ (822)	$ (815)
Net loans and leases	63,647	63,418
Commercial \| Commercial, financial, and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	36,467	35,905
Allowance for loan and lease losses	(353)	(335)	(345)	(345)
Commercial \| Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	31,826	31,202
Commercial \| Commercial and industrial \| Equipment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Property, plant, and equipment and finance lease right-of-use asset	1,500	1,500
Commercial \| Loans to mortgage companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	4,641	4,703
Commercial \| Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,420	13,563
Allowance for loan and lease losses	(156)	(177)	(225)	(227)
Commercial \| Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	157	143
Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,928	14,108
Consumer \| HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	2,163	2,164
Consumer \| Real estate installment loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	11,765	11,944
Consumer \| Credit Card and Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	562	580
Allowance for loan and lease losses	$ (20)	$ (20)	$ (22)	$ (22)