Commitments and Contingencies (Tables)

9 Months Ended

Jun. 30, 2014

Commitments And Contingencies Disclosure [Abstract]

Schedule of Components of Purchase Commitments

Purchase Commitments

Cabot has entered into long-term purchase agreements primarily for the purchase of raw materials. Under certain of these agreements the quantity of material being purchased is fixed, but the price paid changes as market prices change. For those commitments, the amounts included in the table below are based on market prices at June 30, 2014.

	Payments Due by Fiscal Year
	Remainder of Fiscal 2014		2015		2016		2017		2018		Thereafter		Total
	(Dollars in millions)
Reinforcement Materials	$	102	$	318	$	280	$	189	$	181	$	2,628	$	3,698
Performance Materials		12		39		33		29		30		236		379
Advanced Technologies		1		2		1		1		1		—		6
Purification Solutions		12		20		11		10		9		17		79
Total	$	127	$	379	$	325	$	229	$	221	$	2,881	$	4,162