Derivative Financial Instruments - Carrying Value of Hedged Items in Fair Value Hedge (Details) - USD ($) $ in Millions |
Mar. 31, 2025 |
Dec. 31, 2024 |
|---|---|---|
| Derivatives, Fair Value [Line Items] | ||
| Carrying amount of hedged items | $ 14,920 | $ 11,685 |
| Active hedged asset adjustments | (1,043) | (1,283) |
| Discontinued hedged asset adjustments | (230) | (232) |
| Total hedged asset adjustments | $ (1,273) | $ (1,515) |
| Hedged Asset, Statement of Financial Position [Extensible Enumeration] | Securities available-for-sale (includes amortized cost of $28.1 billion and $27.2 billion at March 31, 2025 and December 31, 2024, respectively, an allowance for credit losses of nil at both March 31, 2025 and December 31, 2024, and $1.4 billion and $0.6 billion pledged to creditors at March 31, 2025 and December 31, 2024, respectively) | Securities available-for-sale (includes amortized cost of $28.1 billion and $27.2 billion at March 31, 2025 and December 31, 2024, respectively, an allowance for credit losses of nil at both March 31, 2025 and December 31, 2024, and $1.4 billion and $0.6 billion pledged to creditors at March 31, 2025 and December 31, 2024, respectively) |
| Deposits | ||
| Derivatives, Fair Value [Line Items] | ||
| Carrying amount of hedged liability items | $ 1,483 | $ 1,476 |
| Active hedged liability adjustments | (46) | (61) |
| Discontinued hedged liability adjustments | 29 | 37 |
| Total hedged liability adjustments | $ (17) | $ (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 | $ 9,034 | $ 8,236 |
| Active hedged liability adjustments | (201) | (295) |
| Discontinued hedged liability adjustments | 20 | 31 |
| Total hedged liability adjustments | $ (181) | $ (264) |
| Hedged Liability, Statement of Financial Position [Extensible Enumeration] | Long-term debt (includes $7.5 billion and $7.9 billion designated under fair value option at March 31, 2025 and December 31, 2024, respectively) | Long-term debt (includes $7.5 billion and $7.9 billion designated under fair value option at March 31, 2025 and December 31, 2024, respectively) |