Venezuela	9 Months Ended
Jun. 30, 2014
Equity Method Investments And Joint Ventures [Abstract]
Venezuela	O. Venezuela Cabot owns 49% of an operating Carbon Black affiliate in Venezuela, which is accounted for as an equity affiliate, through wholly owned subsidiaries that carry the investment and receive its dividends. As of June 30, 2014, these subsidiaries carried the operating affiliate investment of $17 million and held 20 million bolivars (less than $1 million) in cash. During the nine months ended June 30, 2014 and 2013, the operating affiliate declared dividends in the amount of $4 million and $2 million, respectively, which were paid in U.S. dollars and repatriated to the Company’s wholly owned subsidiaries. During the second quarter of fiscal 2014, the Venezuelan government enacted several changes to Venezuela’s foreign exchange regime, introducing a multi-tier foreign exchange system whereby there are now three exchange rate mechanisms available to convert Venezuelan Bolivars to U.S. dollars. In March 2014, the Venezuelan government created a currency exchange mechanism referred to as SICAD 2 (Supplementary System for the Administration of Foreign Currency) and allowed its use by all entities for all transactions. The exchange rate on March 31, 2014 under SICAD 2 was 50.8 bolivars to the U.S. dollar (B/$) compared to the previously used official exchange rate of 6.3 B/$. A significant portion of the Company’s operating affiliate’s sales are exports denominated in U.S. dollars. The Venezuelan government mandates that a certain percentage of the dollars collected from these sales be converted into Bolivars. Since the exchange rate that was made available to the Company when converting these dollars into Bolivars was the SICAD 2 exchange rate, the operating affiliate remeasured its bolivar denominated monetary accounts at that rate. From a segment reporting perspective, the negative impact of the exchange rate devaluation on the operating affiliate’s results was $8 million, of which Cabot’s share was $4 million for the nine months ended June 30, 2014. The SICAD 2 rate at June 30, 2014 was 50.0 B/$. In addition, in the second quarter of fiscal 2014 the Company remeasured the bolivar denominated monetary accounts in its wholly owned subsidiaries at the SICAD 2 rate as it was determined that this exchange mechanism is applicable to these subsidiaries. This resulted in the recognition of a $2 million loss which was recorded within Other income within the Consolidated Statements of Operations. The Company also recognized a tax benefit of $2 million from a reduction in its bolivar denominated deferred tax liability due to the impact of the devaluation of the bolivar on unremitted earnings. The operating entity has been profitable historically and has significant export operations from which it is entitled to retain a certain percentage of the foreign currency that it collects, which is principally the U.S. dollar. The Company continues to closely monitor developments in Venezuela and their potential impact on the recoverability of its equity affiliate investment. The Company closely monitors its ability to convert its bolivar holdings into U.S. dollars, as the Company intends to convert substantially all bolivars held by its wholly owned subsidiaries in Venezuela to U.S. dollars as soon as practical. Any future change in the SICAD 2 rate or opening of additional parallel markets could lead the Company to change the exchange rate it uses and result in gains or losses on the bolivar denominated assets held by its wholly owned subsidiaries.

O. Venezuela

Cabot owns 49% of an operating Carbon Black affiliate in Venezuela, which is accounted for as an equity affiliate, through wholly owned subsidiaries that carry the investment and receive its dividends. As of June 30, 2014, these subsidiaries carried the operating affiliate investment of $17 million and held 20 million bolivars (less than $1 million) in cash.

During the nine months ended June 30, 2014 and 2013, the operating affiliate declared dividends in the amount of $4 million and $2 million, respectively, which were paid in U.S. dollars and repatriated to the Company’s wholly owned subsidiaries.

During the second quarter of fiscal 2014, the Venezuelan government enacted several changes to Venezuela’s foreign exchange regime, introducing a multi-tier foreign exchange system whereby there are now three exchange rate mechanisms available to convert Venezuelan Bolivars to U.S. dollars. In March 2014, the Venezuelan government created a currency exchange mechanism referred to as SICAD 2 (Supplementary System for the Administration of Foreign Currency) and allowed its use by all entities for all transactions. The exchange rate on March 31, 2014 under SICAD 2 was 50.8 bolivars to the U.S. dollar (B/$) compared to the previously used official exchange rate of 6.3 B/$. A significant portion of the Company’s operating affiliate’s sales are exports denominated in U.S. dollars. The Venezuelan government mandates that a certain percentage of the dollars collected from these sales be converted into Bolivars. Since the exchange rate that was made available to the Company when converting these dollars into Bolivars was the SICAD 2 exchange rate, the operating affiliate remeasured its bolivar denominated monetary accounts at that rate. From a segment reporting perspective, the negative impact of the exchange rate devaluation on the operating affiliate’s results was $8 million, of which Cabot’s share was $4 million for the nine months ended June 30, 2014. The SICAD 2 rate at June 30, 2014 was 50.0 B/$.

In addition, in the second quarter of fiscal 2014 the Company remeasured the bolivar denominated monetary accounts in its wholly owned subsidiaries at the SICAD 2 rate as it was determined that this exchange mechanism is applicable to these subsidiaries. This resulted in the recognition of a $2 million loss which was recorded within Other income within the Consolidated Statements of Operations. The Company also recognized a tax benefit of $2 million from a reduction in its bolivar denominated deferred tax liability due to the impact of the devaluation of the bolivar on unremitted earnings.

The operating entity has been profitable historically and has significant export operations from which it is entitled to retain a certain percentage of the foreign currency that it collects, which is principally the U.S. dollar. The Company continues to closely monitor developments in Venezuela and their potential impact on the recoverability of its equity affiliate investment.

The Company closely monitors its ability to convert its bolivar holdings into U.S. dollars, as the Company intends to convert substantially all bolivars held by its wholly owned subsidiaries in Venezuela to U.S. dollars as soon as practical. Any future change in the SICAD 2 rate or opening of additional parallel markets could lead the Company to change the exchange rate it uses and result in gains or losses on the bolivar denominated assets held by its wholly owned subsidiaries.