Equity and Noncontrolling Interests - Schedule of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	$ 2,616	$ 2,509	$ 2,546	$ 2,375
Aggregate adjustment for the period, net of tax	(108)	48	43	179
Stockholders' equity, ending balance	2,402	2,532	2,402	2,532
Accumulated Other Comprehensive Income (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(704)	(730)	(842)	(845)
Stockholders' equity, ending balance	(802)	(687)	(802)	(687)
Foreign currency translation adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(725)	(746)	(854)	(836)
Aggregate adjustment for the period, net of tax	(92)	29	37	119
Stockholders' equity, ending balance	(817)	(717)	(817)	(717)
Foreign currency translation adjustments | Net Investment Hedging
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, ending balance	1	73	1	73
Realized and unrealized gains (losses) on derivatives
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	22	17	13	(8)
Current period changes in fair value, net of tax	8	27	29	58
Reclassification to income, net of tax	(14)	(13)	(26)	(19)
Stockholders' equity, ending balance	16	31	16	31
Pension and postretirement plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(1)	(1)	(1)	(1)
Stockholders' equity, ending balance	$ (1)	$ (1)	$ (1)	$ (1)