Loans, Leases, and Allowance for Credit Losses (Summary of Nonaccrual Loans) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	$ 83	$ 91
Amortized cost basis with allowance	178	131
Nonaccrual loans that are current	261	222
Related allowance	52	43
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	36	23
Amortized cost basis with allowance	111	81
Nonaccrual loans that are current	147	104
Related allowance	41	32
Commercial \| Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	23	11
Amortized cost basis with allowance	88	71
Nonaccrual loans that are current	111	82
Related allowance	38	30
Commercial \| Leasing
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	0	0
Amortized cost basis with allowance	2	2
Nonaccrual loans that are current	2	2
Related allowance	1	1
Commercial \| Owner-occupied
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	10	12
Amortized cost basis with allowance	18	8
Nonaccrual loans that are current	28	20
Related allowance	2	1
Commercial \| Municipal
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	3
Amortized cost basis with allowance	3
Nonaccrual loans that are current	6
Related allowance	0
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	33	59
Amortized cost basis with allowance	4	2
Nonaccrual loans that are current	37	61
Related allowance	1	1
Commercial real estate \| Construction and land development
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	0	22
Amortized cost basis with allowance	2	0
Nonaccrual loans that are current	2	22
Related allowance	0	0
Commercial real estate \| Term
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	33	37
Amortized cost basis with allowance	2	2
Nonaccrual loans that are current	35	39
Related allowance	1	1
Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	14	9
Amortized cost basis with allowance	63	48
Nonaccrual loans that are current	77	57
Related allowance	10	10
Consumer \| Home equity credit line
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	5	1
Amortized cost basis with allowance	24	16
Nonaccrual loans that are current	29	17
Related allowance	5	5
Consumer \| 1-4 family residential
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	9	8
Amortized cost basis with allowance	37	32
Nonaccrual loans that are current	46	40
Related allowance	4	$ 5
Consumer \| Bankcard and other revolving plans
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	0
Amortized cost basis with allowance	1
Nonaccrual loans that are current	1
Related allowance	1
Consumer \| Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Amortized cost basis with no allowance	0
Amortized cost basis with allowance	1
Nonaccrual loans that are current	1
Related allowance	$ 0

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.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph c
-Publisher SEC

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

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- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

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- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status with no allowance for credit loss. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

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- Definition

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+ References

No definition available.

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- Definition

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