Postretirement Benefit Plans - Employer Contributions to Plans (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Dec. 31, 2025 |
Dec. 31, 2024 |
Dec. 31, 2025 |
Dec. 31, 2024 |
|
| Contributions to employee benefit plans | ||||
| Funded pension plans | $ 2 | $ 4 | $ 18 | $ 27 |
| Unfunded pension plans | 4 | 3 | 12 | 11 |
| Savings and defined contribution pension plans | 16 | 14 | 49 | 46 |
| Total contributions | $ 22 | $ 21 | $ 79 | $ 84 |