Annual report pursuant to Section 13 and 15(d)

SHAREHOLDERS' EQUITY (Details)

v2.4.1.9
SHAREHOLDERS' EQUITY (Details) (USD $)
Share data in Millions, except Per Share data, unless otherwise specified
12 Months Ended 1 Months Ended 3 Months Ended 1 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jul. 31, 2013
Jul. 31, 2012
Jul. 31, 2011
Dec. 31, 2014
Sep. 28, 2014
Jun. 29, 2014
Mar. 30, 2014
Dec. 31, 2013
Sep. 29, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2012
Sep. 30, 2012
Jul. 01, 2012
Apr. 01, 2012
Jul. 31, 2014
Dec. 31, 2012
Changes in shares of stock                                        
Shares acquired (in shares) 4.8us-gaap_TreasuryStockSharesAcquired                                      
Dividends Paid                                        
Dividend payments on common stock (in dollars) $ 512,000,000us-gaap_PaymentsOfDividends $ 420,000,000us-gaap_PaymentsOfDividends $ 340,000,000us-gaap_PaymentsOfDividends                                  
Employee Benefits Trust                                        
Contributions charged to income (in dollars) 35,000,000us-gaap_AllocatedShareBasedCompensationExpense 34,000,000us-gaap_AllocatedShareBasedCompensationExpense 35,000,000us-gaap_AllocatedShareBasedCompensationExpense                                  
Preferred Stock                                        
Class of Stock                                        
Preferred Stock, Shares Authorized 1us-gaap_PreferredStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= us-gaap_PreferredStockMember
          1us-gaap_PreferredStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= us-gaap_PreferredStockMember
                         
Preference Stock                                        
Class of Stock                                        
Preferred Stock, Shares Authorized 1us-gaap_PreferredStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= cmi_PreferenceStockMember
          1us-gaap_PreferredStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= cmi_PreferenceStockMember
                         
Common Stock                                        
Changes in shares of stock                                        
Balance at beginning of period (in shares) 222.3us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
222.4us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
222.2us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
            222.3us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
      222.4us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
      222.2us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
   
Stock Issued During Period, Shares, New Issues 0.1us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
0.1us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
0.4us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
                                 
Other shareholder transactions (in shares) (0.1)cmi_OtherShareholderTransactions
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
(0.2)cmi_OtherShareholderTransactions
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
(0.2)cmi_OtherShareholderTransactions
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
                                 
Balance at the end of the period (in shares) 222.3us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
222.3us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
222.4us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
      222.3us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
      222.3us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
      222.4us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
        222.4us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
Dividends Paid                                        
Cash dividend (in dollars per share) $ 2.81us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 2.25us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 1.8us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
      $ 0.78us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 0.78us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 0.625us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 0.625us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 0.625us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 0.625us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 0.50us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 0.50us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 0.50us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 0.50us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 0.40us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
$ 0.40us-gaap_CommonStockDividendsPerShareCashPaid
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
   
Employee Benefits Trust                                        
Percentage increase in cash dividend per common share       25.00%cmi_PercentageIncreaseDecrease
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
25.00%cmi_PercentageIncreaseDecrease
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
25.00%cmi_PercentageIncreaseDecrease
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonStockMember
                           
Treasury Stock                                        
Changes in shares of stock                                        
Balance at beginning of period (in shares) 35.6us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
32.6us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
30.2us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
            35.6us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
      32.6us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
      30.2us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
   
Shares acquired (in shares) 4.8us-gaap_TreasuryStockSharesAcquired
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
3.3us-gaap_TreasuryStockSharesAcquired
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
2.6us-gaap_TreasuryStockSharesAcquired
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
                                 
Stock Issued During Period, Shares, New Issues (0.3)us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
(0.3)us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
(0.2)us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
                                 
Balance at the end of the period (in shares) 40.1us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
35.6us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
32.6us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
      40.1us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
      35.6us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
      32.6us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
        32.6us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
Treasury Stock                                        
Treasury Stock Repurchase Authorization Value                                     1,000,000,000cmi_TreasuryStockRepurchaseAuthorizationValue
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
1,000,000,000cmi_TreasuryStockRepurchaseAuthorizationValue
/ us-gaap_StatementClassOfStockAxis
= us-gaap_TreasuryStockMember
Common Stock Held in Trust                                        
Changes in shares of stock                                        
Balance at beginning of period (in shares) 1.3us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
1.5us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
1.8us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
            1.3us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
      1.5us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
      1.8us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
   
Stock Issued During Period, Shares, New Issues (0.2)us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
(0.2)us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
(0.3)us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
                                 
Balance at the end of the period (in shares) 1.1us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
1.3us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
1.5us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
      1.1us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
      1.3us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
      1.5us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
        1.5us-gaap_SharesIssued
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
Employee Benefits Trust                                        
Contributions charged to income (in dollars) $ 24,000,000us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
$ 24,000,000us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember
$ 27,000,000us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_StatementClassOfStockAxis
= cmi_CommonStockHeldInTrustMember