Bank Premises and Equipment - Additional Information (Details) $ in Millions	12 Months Ended
Dec. 31, 2021 USD ($) branch	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Depreciation and amortization expense	$ 270	$ 256	$ 255
Impairment losses on bank premises	$ 7	$ 30	$ 28
Closed In 2021
Property, Plant and Equipment [Line Items]
Number of branches held for sale \| branch	44

Real estate held for sale count.

No definition available.

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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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
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-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

+ Details

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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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

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-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=123351718&loc=d3e2611-110228

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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

No definition available.

+ Details

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