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Equity - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025	Nov. 14, 2024
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Non-cash stock-based compensation expense	$ 2	$ 16	$ 33	$ 43
Non-cash stock-based compensation expense		1		1
Acquisition consideration common shares issued	$ 9		$ 9
Strategic Business
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Business combination, shares issued (in shares)	1,462,666		1,462,666
Share-based compensation nonvested (in shares)	1,164,550		1,164,550
Omnibus Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share repurchase authorized, amount					$ 100
Class A Common Stock \| Omnibus Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Share repurchase authorized, amount					$ 100
Additional Paid-in Capital
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Non-cash stock-based compensation expense		$ 15		$ 42
Acquisition consideration common shares issued (in shares)	298,116		298,116
Acquisition consideration common shares issued	$ 9		$ 9
Common Stock \| Class A Common Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares issued under omnibus incentive plan (in shares)	31,575		1,030,956
Acquisition consideration common shares issued (in shares)	298,000		298,000