Loans - Summary of Subsequently Delinquent Loans With Payment Modifications (Details) - 90+ Days - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Financing Receivable, Modified [Line Items]
Loans modified, subsequently default		$ 0
Commercial loans
Financing Receivable, Modified [Line Items]
Loans modified, subsequently default	$ 1
Commercial loans | Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Loans modified, subsequently default	0
Commercial loans | Principal Forgiveness
Financing Receivable, Modified [Line Items]
Loans modified, subsequently default	0
Commercial loans | Term Extension / Significant Payment Deferral
Financing Receivable, Modified [Line Items]
Loans modified, subsequently default	1
Commercial loans | Combination
Financing Receivable, Modified [Line Items]
Loans modified, subsequently default	0
Commercial loans | Global banking
Financing Receivable, Modified [Line Items]
Loans modified, subsequently default	1
Commercial loans | Global banking | Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Loans modified, subsequently default	0
Commercial loans | Global banking | Principal Forgiveness
Financing Receivable, Modified [Line Items]
Loans modified, subsequently default	0
Commercial loans | Global banking | Term Extension / Significant Payment Deferral
Financing Receivable, Modified [Line Items]
Loans modified, subsequently default	1
Commercial loans | Global banking | Combination
Financing Receivable, Modified [Line Items]
Loans modified, subsequently default	$ 0