Commitments and Contingencies (Details 1) (USD $)
3 Months Ended 12 Months Ended
Mar. 31, 2015
Claimant
Claim
Dec. 31, 2014
Claimant
Respirator Mask/Asbestos Litigation    
Loss contingencies    
Insurance receivables $ 41,000,000  
Total number of named claimants 2,150 2,200
Number of total claims settled and taken to trial 9  
Number of total claims tried to verdict 8  
Number of total claims settled and tried to verdict 7  
Number of total claims dismissed 1  
Increase in insurance liabilities 14,000,000  
Payments for fees and settlements related to litigation 10,000,000  
Respirator Mask/Asbestos Litigation - State of West Virginia    
Loss contingencies    
Amount of liability recorded for unspecified worker's compensation and healthcare benefits 0  
Number of additional defendants 2  
Respirator Mask/Asbestos litigation - Excluding Aearo Technologies    
Loss contingencies    
Accrued loss contingency reserve 144,000,000  
Respirator Mask/Asbestos Litigation - Aearo Technologies    
Loss contingencies    
Accrued loss contingency reserve 23,000,000  
Quarterly fee paid to Cabot to retain responsibility and liability for products manufactured before July 11, 1995 100,000  
Number of underlying claims concerning whether they were Cabot's responsibility 258  
Outstanding issues remaining 2  
Environmental Matters - Remediation    
Loss contingencies    
Accrued loss contingency reserve 27,000,000  
Insurance receivables 11,000,000  
Number of years remediation payments expected to be paid for applicable sites 20 years  
Environmental Matters - Regulatory Activities    
Loss contingencies    
Number of PFCs the EPA has proposed to have public water suppliers monitor 6  
Amount of PFOA in drinking water allowed per provisional health advisories in grams per liter 0.0000004  
Amount of PFOS in drinking water allowed per provisional health advisories in grams per liter 0.0000002  
Number of years after phase-out decision in May 2000 that the Company stopped manufacturing and using vast majority of perfluorooctanyl compounds 2 years  
Environmental Matters - Regulatory Activities | Alabama    
Loss contingencies    
Wastewater treatment plant sludge containing PFCs surrounding Decatur facility pursuant to a permit 20 years  
Environmental Matters - Litigation | Morgan County, Alabama    
Loss contingencies    
Total number of named claimants 3  
Environmental Matters - Litigation | Metropolitan Council, Minnesota    
Loss contingencies    
Number of wastewater treatment plants from which PFC-containing sludge and biosolids may allegedly be discharged by Metropolitan Council, low end of range 1  
Environmental Matters - Other Environmental Litigation    
Loss contingencies    
Accrued loss contingency reserve 41,000,000  
Insurance receivables $ 15,000,000  
Number of former disposal sites with PFC present in soil and groundwater in Washington County, Minnesota 2  
Environmental Matters - Other Environmental Litigation | Maximum    
Loss contingencies    
Number of years remediation payments expected to be paid for applicable sites 4 years