BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2018	Jun. 30, 2018
Statement Of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 319	$ 377
Property and equipment, accumulated depreciation	$ 30,953	$ 29,223
Common stock, shares authorized	24,000,000,000	24,000,000,000
Common stock, outstanding	7,680,000,000	7,677,000,000