XML 16 R1.htm IDEA: XBRL DOCUMENT v3.19.1
Document and Entity Information - USD ($)
$ in Billions
 12 Months Ended
Mar. 31, 2019
Apr. 30, 2019
Sep. 30, 2018
Document And Entity Information [Abstract]      
Entity Registrant Name McKESSON CORPORATION    
Entity Central Index Key 0000927653    
Entity Tax Identification Number 943207296    
Document Type 10-K    
Current Fiscal Year End Date --03-31    
Document Period End Date Mar. 31, 2019    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2019    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Amendment Flag false    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Shell Company false    
Entity Emerging Growth Company false    
Entity Public Float     $ 26
Entity Common Stock, Shares Outstanding   189,961,556