Legal Matters - Schedule of Accrued Litigation for Both Covered and Non-Covered Litigation (Detail) - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | |
|---|---|---|---|
Jun. 30, 2023 |
Jun. 30, 2023 |
Jun. 30, 2022 |
|
| Loss Contingency Accrual [Roll Forward] | |||
| Balance at beginning of period | $ 1,456 | $ 983 | |
| Balance at end of period | $ 1,545 | 1,545 | 1,486 |
| Uncovered Litigation | |||
| Loss Contingency Accrual [Roll Forward] | |||
| Provision for legal matters | 1 | 2 | |
| Covered Litigation | |||
| Loss Contingency Accrual [Roll Forward] | |||
| Provision for legal matters | 808 | 878 | |
| Payments for legal matters | (720) | (377) | |
| U.S. Covered Litigation | |||
| Loss Contingency Accrual [Roll Forward] | |||
| Balance at beginning of period | 1,441 | 881 | |
| Provision for legal matters | 456 | 797 | 861 |
| Payments for legal matters | (699) | (262) | |
| Balance at end of period | 1,539 | 1,539 | 1,480 |
| VE Territory Covered Litigation | |||
| Loss Contingency Accrual [Roll Forward] | |||
| Balance at beginning of period | 11 | 102 | |
| Provision for legal matters | 11 | 17 | |
| Payments for legal matters | (19) | (114) | |
| Balance at end of period | $ 3 | $ 3 | $ 5 |