Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Net sales and other operating revenues	$ 4,321	$ 3,409	$ 2,614
Cost of sales	3,436	2,610	2,114
Gross profit	885	799	500
Selling and administrative expenses	258	289	292
Research and technical expenses	55	56	57
Gain on bargain purchase of a business (Note C)	(24)
Income (loss) from operations	389	454	21
Interest and dividend income	11	8	8
Interest expense	(56)	(49)	(53)
Other income (expense)	(9)	(7)	(9)
Income (loss) from continuing operations before income taxes and equity in earnings of affiliated companies	335	406	(33)
(Provision) benefit for income taxes	(102)	(123)	(191)
Equity in earnings of affiliated companies, net of tax	10	3	3
Net income (loss)	243	286	(221)
Net income (loss) attributable to noncontrolling interests, net of tax of $8, $10 and $4	34	36	17
Net income (loss) attributable to Cabot Corporation	$ 209	$ 250	$ (238)
Weighted-average common shares outstanding:
Basic	56.5	56.7	56.6
Diluted	56.9	56.8	56.6
Earnings (loss) per common share:
Basic	$ 3.65	$ 4.35	$ (4.21)
Diluted	$ 3.62	$ 4.34	$ (4.21)
Specialty Fluids [Member]
Loss on sale and asset impairment charge			$ 1
Purification Solutions [Member]
Loss on sale and asset impairment charge	$ 207
Marshall Mine [Member]
Loss on sale and asset impairment charge			$ 129