Note 1 - Organization and Summary of Significant Accounting Policies - Error Correction (Details) - USD ($) $ in Millions |
3 Months Ended | 6 Months Ended | 9 Months Ended | 12 Months Ended | ||||
|---|---|---|---|---|---|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
Jun. 30, 2026 |
Jun. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Proceeds from short-term debt | $ 776 | $ 195 | $ 2,900 | $ 1,500 | $ 4,920 | $ 6,400 | $ 2,200 | |
| Repayment of short-term debt | $ (615) | (655) | (813) | (2,378) | (1,405) | (4,298) | (5,793) | (2,214) |
| Net cash provided by (used in) financing activities | (2,292) | 95 | (2,368) | 1 | $ (2,396) | (111) | (371) | (90) |
| Previously Reported [Member] | ||||||||
| Net change in short-term debt | (615) | 121 | (618) | 522 | 622 | 607 | (14) | |
| Net cash provided by (used in) financing activities | (2,292) | 95 | (2,368) | 1 | (111) | (371) | (90) | |
| Revision of Prior Period, Error Correction, Adjustment [Member] | ||||||||
| Net change in short-term debt | 615 | (121) | 618 | (522) | (622) | (607) | 14 | |
| Proceeds from short-term debt | 776 | 195 | 2,900 | 4,920 | 6,400 | 2,200 | ||
| Repayment of short-term debt | $ (615) | $ (655) | $ (813) | $ (2,378) | $ (4,298) | $ (5,793) | $ (2,214) | |