Equity and Noncontrolling Interests - Schedule of AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	$ 1,949	$ 2,402	$ 2,443	$ 2,546
Aggregate adjustment for the period, net of tax	151	(72)	18	(29)
Stockholders' equity, ending balance	2,074	2,222	2,074	2,222
Accumulated Other Comprehensive Income (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(814)	(802)	(693)	(842)
Stockholders' equity, ending balance	(674)	(869)	(674)	(869)
Foreign currency translation adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(803)	(817)	(673)	(854)
Aggregate adjustment for the period, net of tax	118	(44)	(12)	(7)
Stockholders' equity, ending balance	(685)	(861)	(685)	(861)
Foreign currency translation adjustments | Net Investment Hedging
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, ending balance	(2)	2	(2)	2
Realized and unrealized gains (losses) on derivatives
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Stockholders' equity, beginning balance	(10)	16	(19)	13
Current period changes in fair value, net of tax	23	(16)	20	13
Reclassification to income, net of tax	(1)	(7)	11	(33)
Stockholders' equity, ending balance	12	(7)	12	(7)
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)