Maturities of lease liabilities (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Jun. 30, 2017
Leases [Abstract]
Operating Leases, Year Ending June 30, 2018 (excluding the nine months ended March 31, 2018)	$ 388
Operating Leases, Year Ending June 30, 2019	1,472
Operating Leases, Year Ending June 30, 2020	1,340
Operating Leases, Year Ending June 30, 2021	1,076
Operating Leases, Year Ending June 30, 2022	887
Operating Leases, Thereafter	2,790
Operating Leases, Total lease payments	7,953
Operating Leases, Less imputed interest	(820)
Operating Leases	7,133	$ 6,795
Finance Leases, Year Ending June 30, 2018 (excluding the nine months ended March 31, 2018)	104
Finance Leases, Year Ending June 30, 2019	384
Finance Leases, Year Ending June 30, 2020	391
Finance Leases, Year Ending June 30, 2021	399
Finance Leases, Year Ending June 30, 2022	406
Finance Leases, Thereafter	4,442
Finance Leases, Total lease payments	6,126
Finance Leases, Less imputed interest	(1,795)
Finance Leases	$ 4,331	$ 2,538