Consolidated Statements Of Operations (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Net sales and other operating revenues	$ 820	[1]	$ 762	[1]
Cost of sales	673		619
Gross profit	147		143
Selling and administrative expenses	73		65
Research and technical expenses	19		17
Income from operations	55		61
Interest and dividend income	1		1
Interest expense	(16)		(10)
Other income	1		3
Income from continuing operations before income taxes and equity in earnings of affiliated companies	41	[2]	55	[2]
Provision for income taxes	(19)		(16)
Equity in earnings of affiliated companies	3		1
Income from continuing operations	25		40
(Loss) income from discontinued operations, net of tax	(1)		11
Net income	24		51
Net income attributable to noncontrolling interests	4		5
Net income attributable to Cabot Corporation	$ 20		$ 46
Weighted-average common shares outstanding, in millions:
Basic	63.5		63.5
Diluted	64.1		64.2
Basic:
Income from continuing operations attributable to Cabot Corporation	$ 0.33		$ 0.55
(Loss) income from discontinued operations	$ (0.02)		$ 0.17
Net income attributable to Cabot Corporation	$ 0.31		$ 0.72
Diluted:
Income from continuing operations attributable to Cabot Corporation	$ 0.33		$ 0.55
(Loss) income from discontinued operations	$ (0.02)		$ 0.16
Net income attributable to Cabot Corporation	$ 0.31		$ 0.71
Dividends per common share	$ 0.20		$ 0.18

[1] Unallocated and other reflects royalties paid by equity affiliates, external shipping and handling fees, and the impact of the corporate adjustment for unearned revenue.

[2] Income (loss) from continuing operations before taxes that is categorized as Unallocated and Other includes: