Revenue Unpaid Incentives (Details) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2025 |
Jun. 30, 2024 |
Jun. 30, 2025 |
Jun. 30, 2024 |
Sep. 30, 2024 |
|
| Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Line Items] | |||||
| Paid Economic Incentives | $ 80 | $ 80 | $ 248 | $ 233 | |
| Unpaid Economic Incentives | $ (197) | $ (197) | $ (187) | ||