Loans, Leases, and Allowance for Credit Losses (Summary of Selected Information on Modified Loans) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 47	$ 103	$ 177	$ 148
Percentage of total loans	0.10%	0.20%	0.30%	0.30%
Unfunded lending commitments on troubled debt restructuring	$ 10	$ 10	$ 10	$ 10
Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	1	0	5
Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis	45	100	165	141
Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis	1	1	2	1
Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	1	0
Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis	1	1	9	1
Commercial
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 30	$ 48	$ 67	$ 69
Percentage of total loans	0.10%	0.20%	0.20%	0.20%
Commercial | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 0	$ 1	$ 0	$ 5
Commercial | Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis	29	47	60	64
Commercial | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Commercial | Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	1	0
Commercial | Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis	1	0	6	0
Commercial | Commercial and industrial
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 28	$ 28	$ 60	$ 43
Percentage of total loans	0.20%	0.20%	0.40%	0.30%
Commercial | Commercial and industrial | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 0	$ 1	$ 0	$ 1
Commercial | Commercial and industrial | Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis	27	27	55	42
Commercial | Commercial and industrial | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Commercial | Commercial and industrial | Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	1	0
Commercial | Commercial and industrial | Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis	1	0	4	0
Commercial | Owner-occupied
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 2	$ 20	$ 4	$ 26
Percentage of total loans	0.00%	0.20%	0.00%	0.30%
Commercial | Owner-occupied | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 0	$ 0	$ 0	$ 4
Commercial | Owner-occupied | Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis	2	20	2	22
Commercial | Owner-occupied | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Commercial | Owner-occupied | Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Commercial | Owner-occupied | Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	2	0
Commercial | Municipal
Financing Receivable, Modifications [Line Items]
Amortized cost basis			$ 3
Percentage of total loans			0.10%
Commercial | Municipal | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis			$ 0
Commercial | Municipal | Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis			3
Commercial | Municipal | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis			0
Commercial | Municipal | Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis			0
Commercial | Municipal | Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis			0
Commercial real estate
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 16	$ 52	$ 105	$ 76
Percentage of total loans	0.10%	0.40%	0.80%	0.60%
Commercial real estate | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 0	$ 0	$ 0	$ 0
Commercial real estate | Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis	16	52	105	76
Commercial real estate | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Commercial real estate | Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Commercial real estate | Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Commercial real estate | Construction and land development
Financing Receivable, Modifications [Line Items]
Amortized cost basis		$ 18	$ 2	$ 18
Percentage of total loans		0.70%	0.10%	0.70%
Commercial real estate | Construction and land development | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis		$ 0	$ 0	$ 0
Commercial real estate | Construction and land development | Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis		18	2	18
Commercial real estate | Construction and land development | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis		0	0	0
Commercial real estate | Construction and land development | Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis		0	0	0
Commercial real estate | Construction and land development | Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis		0	0	0
Commercial real estate | Term
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 16	$ 34	$ 103	$ 58
Percentage of total loans	0.10%	0.30%	1.00%	0.60%
Commercial real estate | Term | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 0	$ 0	$ 0	$ 0
Commercial real estate | Term | Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis	16	34	103	58
Commercial real estate | Term | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Commercial real estate | Term | Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Commercial real estate | Term | Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Consumer
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 1	$ 3	$ 5	$ 3
Percentage of total loans	0.00%	0.00%	0.00%	0.00%
Consumer | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 0	$ 0	$ 0	$ 0
Consumer | Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	1	0	1
Consumer | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis	1	1	2	1
Consumer | Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Consumer | Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	1	3	1
Consumer | Home equity credit line
Financing Receivable, Modifications [Line Items]
Amortized cost basis			$ 1
Percentage of total loans			0.00%
Consumer | Home equity credit line | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis			$ 0
Consumer | Home equity credit line | Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis			0
Consumer | Home equity credit line | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis			0
Consumer | Home equity credit line | Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis			0
Consumer | Home equity credit line | Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis			1
Consumer | 1-4 family residential
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 1	$ 2	$ 4	$ 2
Percentage of total loans	0.00%	0.00%	0.00%	0.00%
Consumer | 1-4 family residential | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 0	$ 0	$ 0	$ 0
Consumer | 1-4 family residential | Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Consumer | 1-4 family residential | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis	1	1	2	1
Consumer | 1-4 family residential | Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis	0	0	0	0
Consumer | 1-4 family residential | Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis	$ 0	1	$ 2	1
Consumer | Bankcard and other revolving plans
Financing Receivable, Modifications [Line Items]
Amortized cost basis		$ 1		$ 1
Percentage of total loans		0.20%		0.20%
Consumer | Bankcard and other revolving plans | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Amortized cost basis		$ 0		$ 0
Consumer | Bankcard and other revolving plans | Maturity or term extension
Financing Receivable, Modifications [Line Items]
Amortized cost basis		1		1
Consumer | Bankcard and other revolving plans | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Amortized cost basis		0		0
Consumer | Bankcard and other revolving plans | Payment deferral
Financing Receivable, Modifications [Line Items]
Amortized cost basis		0		0
Consumer | Bankcard and other revolving plans | Multiple modification types
Financing Receivable, Modifications [Line Items]
Amortized cost basis		$ 0		$ 0