Loans and asset quality - Loan Distribution and Industry Concentrations (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 69,829	$ 67,787
Unearned income on lease financings	238	240
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,135	2,128
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	6,299	6,033
Financial institutions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	11,105	10,232
Lease financings
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	702	731
Wealth management loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	10,676	9,792
Wealth management mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	8,878	8,200
Other residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	356	299
Capital call financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,985	2,284
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,884	2,541
Overdrafts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	5,100	3,060
Margin loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 17,709	$ 22,487