Equity Items - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Equity [Abstract]
Unrealized translation gain (loss), before tax	$ 27	$ (5)	$ 110	$ (22)
Unrealized translation gain (loss), tax	0	0	(1)	1
Unrealized translation gain (loss), net of tax	27	(5)	109	(21)
Unrealized gain (loss) on commodity hedges, before tax	(4)	6	(9)	1
Unrealized gain (loss) on commodity hedges, tax	1	(1)	2	0
Unrealized gain (loss) on commodity hedges, net of tax	(3)	5	(7)	1
Total other comprehensive income (loss), before tax	23	1	101	(21)
Total other comprehensive income (loss), tax	1	(1)	1	1
Other comprehensive income (loss) - Note N	$ 24	$ 0	$ 102	$ (20)