Loans and Related Allowance for Credit Losses (Aging Analysis) (Details) - USD ($) $ in Millions	Jun. 30, 2024	Jun. 30, 2023
Financing Receivable [Line Items]
Financing receivable, aging analysis	$ 3,171	$ 1,275
Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	2,360	1,037
30-59 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	6	3
60-89 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	12	7
90 Days or More Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	8	5
Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	785	223
Total commercial
Financing Receivable [Line Items]
Financing receivable, aging analysis	2,973	1,149
Total commercial | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	2,296	1,014
Total commercial | 30-59 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	1
Total commercial | 60-89 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	8	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	668	130
Total commercial | Commercial and industrial
Financing Receivable [Line Items]
Financing receivable, aging analysis	1,562	596
Total commercial | Commercial and industrial | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	1,318	494
Total commercial | Commercial and industrial | 30-59 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	1
Total commercial | Commercial and industrial | 60-89 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	8	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	235	97
Total commercial | Commercial real estate
Financing Receivable [Line Items]
Financing receivable, aging analysis	1,411	553
Total commercial | Commercial real estate | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	978	520
Total commercial | Commercial real estate | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	433	33
Total consumer
Financing Receivable [Line Items]
Financing receivable, aging analysis	198	126
Total consumer | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	64	23
Total consumer | 30-59 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	5	3
Total consumer | 60-89 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	4	3
Total consumer | 90 Days or More Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	8	4
Total consumer | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	117	93
Total consumer | Residential real estate
Financing Receivable [Line Items]
Financing receivable, aging analysis	97	78
Total consumer | Residential real estate | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	9	1
Total consumer | Residential real estate | 30-59 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	1
Total consumer | Residential real estate | 60-89 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis
Total consumer | Residential real estate | 90 Days or More 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	86	77
Total consumer | Home equity
Financing Receivable [Line Items]
Financing receivable, aging analysis	32	15
Total consumer | Home equity | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	3
Total consumer | Home equity | 90 Days or More Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis
Total consumer | Home equity | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	29	15
Total consumer | Credit card
Financing Receivable [Line Items]
Financing receivable, aging analysis	61	30
Total consumer | Credit card | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	45	20
Total consumer | Credit card | 30-59 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	4	3
Total consumer | Credit card | 60-89 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	4	3
Total consumer | Credit card | 90 Days or More Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	7	4
Total consumer | Credit card | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	1
Total consumer | Education
Financing Receivable [Line Items]
Financing receivable, aging analysis	6	2
Total consumer | Education | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	6	2
Total consumer | Education | 30-59 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis
Total consumer | Education | 90 Days or More Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis
Total consumer | Other consumer
Financing Receivable [Line Items]
Financing receivable, aging analysis	2	1
Total consumer | Other consumer | Current or Less Than 30 Days Past Due
Financing Receivable [Line Items]
Financing receivable, aging analysis	1
Total consumer | Other consumer | Nonperforming Loans
Financing Receivable [Line Items]
Financing receivable, aging analysis	$ 1	$ 1