v3.19.1
Document and Entity Information - USD ($)
12 Months Ended
Mar. 31, 2019
May 22, 2019
Sep. 28, 2018
Entity Information [Line Items]      
Entity Registrant Name Booz Allen Hamilton Holding Corp    
Entity Central Index Key 0001443646    
Document Type 10-K    
Document Period End Date Mar. 31, 2019    
Amendment Flag false    
Document Fiscal Year Focus 2019    
Document Fiscal Period Focus FY    
Current Fiscal Year End Date --03-31    
Entity Filer Category Large Accelerated Filer    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Small Business false    
Entity Emerging Growth Company false    
Entity Shell Company false    
Entity Public Float     $ 6,933,296,946
Class A Common Stock      
Entity Information [Line Items]      
Entity Common Stock, Shares Outstanding   140,030,725  
Class B Non-Voting Common Stock      
Entity Information [Line Items]      
Entity Common Stock, Shares Outstanding   0  
Class C Restricted Common Stock      
Entity Information [Line Items]      
Entity Common Stock, Shares Outstanding   0  
Class E Special Voting Common Stock      
Entity Information [Line Items]      
Entity Common Stock, Shares Outstanding   0