Loans - Wholesale Loan Portfolio, Payment Status of FDMs (Details) - Wholesale - USD ($) $ in Millions	Jun. 30, 2026	Jun. 30, 2025
Secured by real estate
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	$ 292	$ 875
Secured by real estate \| Criticized nonaccrual
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	61	288
Secured by real estate \| Current and less than 30 days past due and still accruing
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	227	585
Secured by real estate \| 30–89 days past due and still accruing
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	0	0
Secured by real estate \| 90 or more days past due and still accruing
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	4	2
Commercial and industrial
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	2,110	2,312
Commercial and industrial \| Criticized nonaccrual
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	718	689
Commercial and industrial \| Current and less than 30 days past due and still accruing
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	1,389	1,612
Commercial and industrial \| 30–89 days past due and still accruing
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	3	9
Commercial and industrial \| 90 or more days past due and still accruing
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	0	2
Other
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	207	360
Other \| Criticized nonaccrual
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	95	40
Other \| Current and less than 30 days past due and still accruing
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	109	320
Other \| 30–89 days past due and still accruing
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	3	0
Other \| 90 or more days past due and still accruing
Financing Receivable, Modified [Line Items]
Amortized cost of FDMs during the last 12 months	$ 0	$ 0