Fair Value Option - Additional Information (Detail) - USD ($) |
3 Months Ended | ||
|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Dec. 31, 2025 |
|
| Fair Value [Line Items] | |||
| Total contractual amount of unfunded commitments for which the fair value option was elected | $ 802,000,000 | $ 944,000,000 | |
| Net gain/(loss) attributable to changes in instrument-specific credit spreads on loans and lending commitments for which the fair value option was elected | 0 | $ 0 | |
| Secured long term borrowings | |||
| Fair Value [Line Items] | |||
| Difference between aggregate contractual principal amount of long-term debt instruments for which the fair value option was elected and related fair value | 0 | 0 | |
| Unsecured long-term borrowings | |||
| Fair Value [Line Items] | |||
| Difference between aggregate contractual principal amount of long-term debt instruments for which the fair value option was elected and related fair value | $ (4,260,000,000) | $ (2,860,000,000) | |