v3.21.2
Pension and Other Postretirement Benefits - Change in Pension Benefit Obligations, Plan Assets, Funded Status and Amounts Recognized in the Consolidated Balance Sheets (Detail) - USD ($)
$ in Millions
 12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2019
U.S. Plans      
Change in Benefit Obligation      
Benefit obligation at beginning of period $ 920 $ 919  
Service cost 0 0 $ 0
Interest cost 25 28 32
Actuarial (gain) loss (8) 37  
Benefit payments (60) (64)  
Foreign currency exchange rate changes 0 0  
Benefit obligation at end of period 877 920 919
Accumulated benefit obligation 877 920  
Change in plan assets:      
Fair value of plan assets at beginning of period 1,142 1,090  
Actual return on plan assets 205 114  
Company contribution 1 2  
Benefit payments (60) (64)  
Foreign currency exchange rate changes 0 0  
Fair value of plan assets at end of period 1,288 1,142 1,090
Funded status at end of period 411 222  
Recognized in consolidated balance sheets:      
Non-current asset 417 229  
Current liability (1) (1)  
Non-current liability (5) (6)  
Funded status at end of period 411 222  
Non-U.S. Plans      
Change in Benefit Obligation      
Benefit obligation at beginning of period 563 528  
Service cost 4 4 4
Interest cost 10 10 13
Actuarial (gain) loss (53) 11  
Benefit payments (28) (17)  
Foreign currency exchange rate changes 24 27  
Benefit obligation at end of period 520 563 528
Accumulated benefit obligation 520 563  
Change in plan assets:      
Fair value of plan assets at beginning of period 525 490  
Actual return on plan assets 9 5  
Company contribution 21 22  
Benefit payments (28) (17)  
Foreign currency exchange rate changes 21 25  
Fair value of plan assets at end of period 548 525 $ 490
Funded status at end of period 28 (38)  
Recognized in consolidated balance sheets:      
Non-current asset 30 0  
Current liability 0 0  
Non-current liability (2) (38)  
Funded status at end of period $ 28 $ (38)