Annual report pursuant to Section 13 and 15(d)

COMMITMENTS AND CONTINGENCIES (Details)

v2.4.1.9
COMMITMENTS AND CONTINGENCIES (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
U.S. Distributor Commitments    
Commitments and contingencies:    
Licensing agreement term 3 years  
Number of days in which distributors can terminate agreements without cause 60 days  
Number of days in which distributors can terminate agreements with cause 30 days  
Other Guarantees and Commitments    
Commitments and contingencies:    
Guarantee obligations, maximum potential loss 5us-gaap_GuaranteeObligationsMaximumExposure
/ us-gaap_GuaranteeObligationsByNatureAxis
= cmi_MiscellaneousGuaranteesMember
 
Long-term purchase commitment, penalty exposure 79cmi_LongTermPurchaseCommitmentRemainingAmountOfPenalty
/ us-gaap_GuaranteeObligationsByNatureAxis
= cmi_MiscellaneousGuaranteesMember
 
Commodity Contract Liability Noncurrent 96cmi_CommodityContractLiabilityNoncurrent
/ us-gaap_GuaranteeObligationsByNatureAxis
= cmi_MiscellaneousGuaranteesMember
 
Engine parts supplier    
Commitments and contingencies:    
Long-term purchase commitment, penalty exposure 41cmi_LongTermPurchaseCommitmentRemainingAmountOfPenalty
/ us-gaap_GuaranteeObligationsByNatureAxis
= cmi_EnginePartsSupplierMember
 
Performance bonds and other performance-related guarantees    
Commitments and contingencies:    
Guarantee obligations, current carrying value 76us-gaap_GuaranteeObligationsCurrentCarryingValue
/ us-gaap_GuaranteeObligationsByNatureAxis
= us-gaap_PerformanceGuaranteeMember
$ 66us-gaap_GuaranteeObligationsCurrentCarryingValue
/ us-gaap_GuaranteeObligationsByNatureAxis
= us-gaap_PerformanceGuaranteeMember