Loans and asset quality - Loan Modifications (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, modifications, CARES Act	$ 3	$ 0
Unpaid principal balance		$ 122

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Balance Type:	na
Period Type:	duration