Derivative Financial Instruments - Carrying Value of Hedged Items in Fair Value Hedge (Details) - USD ($) $ in Millions |
Jun. 30, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Derivatives, Fair Value [Line Items] | ||
| Carrying amount of hedged items | $ 16,447 | $ 11,685 |
| Active hedged asset adjustments | (934) | (1,283) |
| Discontinued hedged asset adjustments | (258) | (232) |
| Total hedged asset adjustments | $ (1,192) | $ (1,515) |
| Hedged Asset, Statement of Financial Position [Extensible Enumeration] | Securities available-for-sale (includes amortized cost of $31.0 billion and $27.2 billion at June 30, 2025 and December 31, 2024, respectively, an allowance for credit losses of nil at both June 30, 2025 and December 31, 2024, and $1.9 billion and $0.6 billion pledged to creditors at June 30, 2025 and December 31, 2024, respectively) | Securities available-for-sale (includes amortized cost of $31.0 billion and $27.2 billion at June 30, 2025 and December 31, 2024, respectively, an allowance for credit losses of nil at both June 30, 2025 and December 31, 2024, and $1.9 billion and $0.6 billion pledged to creditors at June 30, 2025 and December 31, 2024, respectively) |
| Deposits | ||
| Derivatives, Fair Value [Line Items] | ||
| Carrying amount of hedged liability items | $ 1,487 | $ 1,476 |
| Active hedged liability adjustments | (34) | (61) |
| Discontinued hedged liability adjustments | 21 | 37 |
| Total hedged liability adjustments | $ (13) | $ (24) |
| Hedged Liability, Statement of Financial Position [Extensible Enumeration] | Deposits | Deposits |
| Long-term debt | ||
| Derivatives, Fair Value [Line Items] | ||
| Carrying amount of hedged liability items | $ 10,064 | $ 8,236 |
| Active hedged liability adjustments | (94) | (295) |
| Discontinued hedged liability adjustments | 9 | 31 |
| Total hedged liability adjustments | $ (85) | $ (264) |
| Hedged Liability, Statement of Financial Position [Extensible Enumeration] | Long-term debt (includes $8.2 billion and $7.9 billion designated under fair value option at June 30, 2025 and December 31, 2024, respectively) | Long-term debt (includes $8.2 billion and $7.9 billion designated under fair value option at June 30, 2025 and December 31, 2024, respectively) |