Maturities of lease liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Jun. 30, 2017
Leases [Abstract]
Operating Leases, Year Ending June 30, 2018 (excluding the six months ended December 31, 2017)	$ 750
Operating Leases, Year Ending June 30, 2019	1,413
Operating Leases, Year Ending June 30, 2020	1,287
Operating Leases, Year Ending June 30, 2021	1,025
Operating Leases, Year Ending June 30, 2022	839
Operating Leases, Thereafter	2,634
Operating Leases, Total lease payments	7,948
Operating Leases, Less imputed interest	(965)
Operating Leases	6,983	$ 6,795
Finance Leases, Year Ending June 30, 2018 (excluding the six months ended December 31, 2017)	167
Finance Leases, Year Ending June 30, 2019	340
Finance Leases, Year Ending June 30, 2020	347
Finance Leases, Year Ending June 30, 2021	353
Finance Leases, Year Ending June 30, 2022	360
Finance Leases, Thereafter	3,857
Finance Leases, Total lease payments	5,424
Finance Leases, Less imputed interest	(1,522)
Finance Leases	$ 3,902	$ 2,538