Bank Premises and Equipment - Additional Information (Details) $ in Millions	12 Months Ended
Dec. 31, 2024 USD ($) banking_location	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 306	$ 292	$ 273
Impairment losses on bank premises	$ 1	2	$ 9
Closed In 2024
Property, Plant and Equipment [Line Items]
Number of branches held for sale \| banking_location	32
Land and improvements held for sale
Property, Plant and Equipment [Line Items]
Impairment losses on bank premises		$ 8

Real estate held for sale count.

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- Definition

The expense recognized in the current period that allocates the cost of nonproduction tangible assets over their useful lives.

+ References

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- Definition

The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 2: http://www.xbrl.org/2003/role/exampleRef
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-Publisher FASB
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
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-Name Accounting Standards Codification
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