Debt - Additional Information (Detail) - USD ($)
9 Months Ended 12 Months Ended
Mar. 31, 2016
Jun. 30, 2015
Debt Instrument [Line Items]    
Commercial paper $ 5,500,000,000 $ 5,000,000,000
Credit facility, financial covenant As of March 31, 2016, we were in compliance with the only financial covenant in both credit agreements, which requires us to maintain a coverage ratio of at least three times earnings before interest, taxes, depreciation, and amortization to interest expense, as defined in the credit agreements.  
Credit facility, drawn $ 0 0
Long-term debt 40,900,000,000 30,300,000,000
Long-term debt fair value 43,500,000,000 30,500,000,000
Unamortized discount 169,000,000 $ 156,000,000
Credit Facility Expire on November 1st 2016    
Debt Instrument [Line Items]    
Credit facility $ 5,000,000,000  
Credit facility, expiration date Nov. 01, 2016  
Credit Facility Expire on November 14th 2018    
Debt Instrument [Line Items]    
Credit facility $ 5,000,000,000  
Credit facility, expiration date Nov. 14, 2018  
Commercial paper    
Debt Instrument [Line Items]    
Commercial paper, weighted average interest rate 0.36% 0.11%
Commercial paper | Lower Limit    
Debt Instrument [Line Items]    
Commercial paper, maturity term 26 days 8 days
Commercial paper | Upper Limit    
Debt Instrument [Line Items]    
Commercial paper, maturity term 91 days 63 days