Maturities of lease liabilities (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Jun. 30, 2018
Leases [Abstract]
Operating Leases, Year Ending June 30, 2019 (excluding the three months ended September 30, 2018)	$ 1,170
Operating Leases, Year Ending June 30, 2020	1,422
Operating Leases, Year Ending June 30, 2021	1,154
Operating Leases, Year Ending June 30, 2022	958
Operating Leases, Year Ending June 30, 2023	786
Operating Leases, Thereafter	2,290
Operating Leases, Total lease payments	7,780
Operating Leases, Less imputed interest	(756)
Operating Leases	7,024	$ 6,967
Finance Leases, Year Ending June 30, 2019 (excluding the three months ended September 30, 2018)	314
Finance Leases, Year Ending June 30, 2020	426
Finance Leases, Year Ending June 30, 2021	434
Finance Leases, Year Ending June 30, 2022	442
Finance Leases, Year Ending June 30, 2023	444
Finance Leases, Thereafter	4,434
Finance Leases, Total lease payments	6,494
Finance Leases, Less imputed interest	(1,820)
Finance Leases	$ 4,674	$ 4,301