Shareholders' Equity - Schedule of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Beginning balance	$ 615	$ 495
Other comprehensive loss before reclassification	(15)	57
Amounts reclassified from accumulated other comprehensive loss	3	2
Net current-period other comprehensive income	(12)	59
Ending Balance	638	565
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Beginning balance	(105)	(129)
Other comprehensive loss before reclassification	(14)	55
Amounts reclassified from accumulated other comprehensive loss	0	0
Net current-period other comprehensive income	(14)	55
Ending Balance	(119)	(74)
Employee Benefit Related Adjustments
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Beginning balance	(526)	(483)
Other comprehensive loss before reclassification	(1)	1
Amounts reclassified from accumulated other comprehensive loss	2	2
Net current-period other comprehensive income	1	3
Ending Balance	(525)	(480)
Unrealized Income (Loss) on cash flow hedges
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Beginning balance	(1)	(2)
Other comprehensive loss before reclassification	0	1
Amounts reclassified from accumulated other comprehensive loss	1	0
Net current-period other comprehensive income	1	1
Ending Balance	0	(1)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Beginning balance	(632)	(614)
Ending Balance	$ (644)	$ (555)