Income Taxes - Temporary Differences and Carryforwards (Details) - USD ($) $ in Millions	Sep. 30, 2022	Sep. 30, 2021
Deferred tax assets:
Accrued expenses and reserves	$ 87	$ 126
Employee and retiree benefits	38	52
Net operating loss and other credit carryforwards	1,226	1,056
Property, plant and equipment	113	159
Intangible assets	150	181
Operating lease liabilities	61	79
Research and development	27	23
Other	2	12
Deferred tax assets:	1,704	1,688
Valuation allowances	(1,662)	(1,637)
Deferred tax assets, net	42	51
Deferred tax liabilities:
Unremitted earnings of foreign subsidiaries	35	32
Indirect tax credits	25	18
Foreign currency adjustments	8	0
Operating lease right-of-use assets	61	79
Deferred tax liabilities:	129	129
Net deferred tax asset/(liability)	$ (87)	$ (78)