Loans and Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest	$ 252	$ 252		$ 226
Net loans and leases	60,558	60,558		57,417
Loans and leases	61,295	61,295		58,102
Allowance for credit loss, writeoff, collateral		1	$ 2
Post-Modification Outstanding Recorded  Investment		25		85
C&I | Collateral Pledged
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 249	$ 249		124
Commercial: | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades	1	1
Commercial: | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial loan grades	16	16
Commercial: | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 33,116	$ 33,116		31,781
Commercial: | Commercial and industrial | Loans to mortgage companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 2,691	$ 2,691		2,258
Percentage contributed	20.00%	20.00%
Commercial: | Commercial and industrial | Finance And Insurance Companies
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 4,100	$ 4,100
Commercial: | Commercial and industrial | C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	30,425	30,425		29,523
Post-Modification Outstanding Recorded  Investment				24
Commercial: | Commercial and industrial | C&I | Collateral Pledged
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	173	173
Commercial: | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,891	13,891		13,228
Commercial: | Commercial real estate | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,891	13,891		13,228
Commercial: | Commercial real estate | CRE | Collateral Pledged
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	76	76
Commercial: | Consumer Real Estate | CRE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Post-Modification Outstanding Recorded  Investment				1
Consumer:
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,475	13,475		12,253
Consumer: | Consumer Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	13,475	13,475		12,253
Consumer: | Consumer Real Estate | HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	2,197	2,197		2,028
Post-Modification Outstanding Recorded  Investment				7
Consumer: | Consumer Real Estate | Real estate installment loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	11,278	11,278		10,225
Post-Modification Outstanding Recorded  Investment				41
Asset Pledged as Collateral
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net loans and leases	44,000	44,000		38,300
Asset Pledged as Collateral | C&I
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, allowance for credit loss, writeoff, collateral	12	24
Asset Pledged as Collateral | HELOC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	7	7		7
Asset Pledged as Collateral | Real estate installment loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$ 27	$ 27		$ 26