Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Net sales and other operating revenues	$ 965	$ 968
Cost of sales	784	770
Gross profit	181	198
Selling and administrative expenses	60	71
Research and technical expenses	13	13
Loss on sale of business and asset impairment charge (Note D)	3	197
Income (loss) from operations	105	(83)
Interest and dividend income	6	3
Interest expense	(22)	(12)
Other income (expense)	(5)	(1)
Income (loss) before income taxes and equity in earnings of affiliated companies	84	(93)
(Provision) benefit for income taxes	(20)	12
Equity in earnings of affiliated companies, net of tax	2	1
Net income (loss)	66	(80)
Net income (loss) attributable to noncontrolling interests, net of tax	12	9
Net income (loss) attributable to Cabot Corporation	$ 54	$ (89)
Weighted-average common shares outstanding:
Basic	56.3	56.8
Diluted	56.7	56.8
Earnings (loss) per common share:
Basic	$ 0.94	$ (1.57)
Diluted	$ 0.93	$ (1.57)