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Basis of Presentation - Additional Information (Detail)
 1 Months Ended
Dec. 31, 2014
Segments
Nov. 30, 2013
Basis Of Presentation [Line Items]    
Number of reporting segments 4us-gaap_NumberOfReportableSegments  
NHUMO [Member]    
Basis Of Presentation [Line Items]    
Percentage acquisition   60.00%us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
/ us-gaap_BusinessAcquisitionAxis
= cbt_NhumoMember
Ownership percentage prior to acquisition   40.00%us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage
/ us-gaap_BusinessAcquisitionAxis
= cbt_NhumoMember