v3.26.1
Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
AOCI Attributable to Parent, Net of Tax        
Balance, beginning of period     $ 4,786  
Other comprehensive income (loss) $ 3 $ 87 (9) $ 72
Balance, end of period 5,222 4,884 5,222 4,884
Total        
AOCI Attributable to Parent, Net of Tax        
Balance, beginning of period (185) (268) (173) (253)
Other comprehensive income (loss) before reclassification adjustments 5 87 (4) 73
Amounts reclassified from AOCI (2) 0 (5) (1)
Other comprehensive income (loss) 3 87 (9) 72
Balance, end of period (182) (181) (182) (181)
Postretirement Benefit Plans        
AOCI Attributable to Parent, Net of Tax        
Balance, beginning of period 23 10 23 10
Other comprehensive income (loss) before reclassification adjustments 0 0 0 0
Amounts reclassified from AOCI (1) 1 (1) 1
Other comprehensive income (loss) (1) 1 (1) 1
Balance, end of period 22 11 22 11
Derivative Instruments        
AOCI Attributable to Parent, Net of Tax        
Balance, beginning of period (9) (13) (15) (23)
Other comprehensive income (loss) before reclassification adjustments 7 (2) 16 9
Amounts reclassified from AOCI (1) (1) (4) (2)
Other comprehensive income (loss) 6 (3) 12 7
Balance, end of period (3) (16) (3) (16)
Foreign Currency        
AOCI Attributable to Parent, Net of Tax        
Balance, beginning of period (199) (265) (181) (240)
Other comprehensive income (loss) before reclassification adjustments (2) 89 (20) 64
Amounts reclassified from AOCI 0 0 0 0
Other comprehensive income (loss) (2) 89 (20) 64
Balance, end of period $ (201) $ (176) $ (201) $ (176)