Document and Entity Information Document - shares
6 Months Ended
Mar. 31, 2017
Apr. 17, 2017
Document and Entity Information [Abstract]    
Entity Registrant Name ROCKWELL COLLINS INC  
Entity Central Index Key 0001137411  
Document and Entity Information --09-30  
Entity Filer Category Large Accelerated Filer  
Entity Registrant Name 10-Q  
Document Period End Date Mar. 31, 2017  
Document Fiscal Year Focus 2017  
Document Fiscal Period Focus Q2  
Amendment Flag false  
Entity Common Stock, Shares Outstanding   162,383,463
Well known seasoned issuer Yes  
Voluntary filer No  
Current reporting status Yes