v3.8.0.1
Document and Entity Information - USD ($)
12 Months Ended
Mar. 31, 2018
May 23, 2018
Sep. 29, 2017
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, 2018    
Amendment Flag false    
Document Fiscal Year Focus 2018    
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 Public Float     $ 5,293,214,554
Class A Common Stock      
Entity Information [Line Items]      
Entity Common Stock, Shares Outstanding   143,367,775  
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