Investment Securities (Details 2) - USD ($) $ in Millions |
Mar. 31, 2022 |
Dec. 31, 2021 |
|---|---|---|
| Debt Securities, Available-for-sale [Line Items] | ||
| Estimated Fair Value, Less than 12 months | $ 3,038 | $ 477 |
| Gross Unrealized Losses, Less than 12 months | (17) | (1) |
| State and municipal obligations | ||
| Debt Securities, Available-for-sale [Line Items] | ||
| Estimated Fair Value, Less than 12 months | 44 | 0 |
| Gross Unrealized Losses, Less than 12 months | (4) | 0 |
| U.S. Government treasury obligations | ||
| Debt Securities, Available-for-sale [Line Items] | ||
| Estimated Fair Value, Less than 12 months | 2,554 | 477 |
| Gross Unrealized Losses, Less than 12 months | (12) | (1) |
| Foreign government bonds and obligations | ||
| Debt Securities, Available-for-sale [Line Items] | ||
| Estimated Fair Value, Less than 12 months | 440 | 0 |
| Gross Unrealized Losses, Less than 12 months | $ (1) | $ 0 |