Loans Held for Sale - Summary (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	$ 1,378	$ 1,925
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	1,377	1,923
Commercial loans | Commercial mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	422	1,252
Commercial loans | Business and corporate banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	955	671
Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for sale	$ 1	$ 2