Loans - Components of Loans (Details) - USD ($) $ in Millions	Jun. 30, 2026	Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	$ 62,103	$ 59,894
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	41,671	39,344
Commercial loans \| Commercial mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	944	1,439
Commercial loans \| Business and corporate banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	30,926	28,305
Commercial loans \| Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	9,801	9,600
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	20,432	20,550
Consumer loans \| Residential mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	19,584	19,789
Consumer loans \| Other Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	848	761
Affiliates \| Commercial loans \| Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	6,411	6,035
Other \| Commercial loans \| Other commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net	$ 3,390	$ 3,565