Bank Loans and Related Allowance for Credit Losses - Convert to Amortizing Loans (Details) - USD ($) $ in Millions |
12 Months Ended | |
|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Total loans | $ 57,991 | $ 45,236 |
| Residential real estate | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Total loans | 30,911 | 27,813 |
| HELOCs | Residential real estate | ||
| Accounts, Notes, Loans and Financing Receivable [Line Items] | ||
| Converted to an amortizing loan by period end | 115 | |
| Within 1 year | 13 | |
| > 1 year – 3 years | 35 | |
| > 3 years – 5 years | 56 | |
| > 5 years | 208 | |
| Total loans | 427 | $ 424 |
| Converted to amortizing loans during the period | $ 13 |