Loans and Related Allowance for Credit Losses (Aging Analysis) (Details) $ in Millions	Jun. 30, 2023 USD ($)
Financing Receivable [Line Items]
Financing receivable, aging analysis	$ 1,275
Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	1,037
30-59 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	3
60-89 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	7
90 Days or More Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	5
Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	223
Total commercial
Financing Receivable [Line Items]
Financing receivable, aging analysis	1,149
Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	1,014
Total commercial | 60-89 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	4
Total commercial | 90 Days or More Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	1
Total commercial | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	130
Total commercial | Commercial and industrial
Financing Receivable [Line Items]
Financing receivable, aging analysis	596
Total commercial | Commercial and industrial | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	494
Total commercial | Commercial and industrial | 60-89 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	4
Total commercial | Commercial and industrial | 90 Days or More Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	1
Total commercial | Commercial and industrial | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	97
Total commercial | Commercial real estate
Financing Receivable [Line Items]
Financing receivable, aging analysis	553
Total commercial | Commercial real estate | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	520
Total commercial | Commercial real estate | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	33
Total consumer
Financing Receivable [Line Items]
Financing receivable, aging analysis	126
Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	23
Total consumer | 30-59 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	3
Total consumer | 60-89 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	3
Total consumer | 90 Days or More Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	4
Total consumer | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	93
Total consumer | Residential real estate
Financing Receivable [Line Items]
Financing receivable, aging analysis	78
Total consumer | Residential real estate | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	1
Total consumer | Residential real estate | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	77
Total consumer | Home equity
Financing Receivable [Line Items]
Financing receivable, aging analysis	15
Total consumer | Home equity | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	15
Total consumer | Credit card
Financing Receivable [Line Items]
Financing receivable, aging analysis	30
Total consumer | Credit card | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	20
Total consumer | Credit card | 30-59 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	3
Total consumer | Credit card | 60-89 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	3
Total consumer | Credit card | 90 Days or More Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	4
Total consumer | Education
Financing Receivable [Line Items]
Financing receivable, aging analysis	2
Total consumer | Education | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	2
Total consumer | Other consumer
Financing Receivable [Line Items]
Financing receivable, aging analysis	1
Total consumer | Other consumer | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	$ 1