Reconciliation of Total Assets Measured at Fair Value on Recurring Basis to Balance Sheet Presentation (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Jun. 30, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net fair value of assets measured at fair value on a recurring basis	$ 141,388	$ 133,985
Other	1	1
Recorded basis of investment components	146,741	139,004
Other Current and Long-term Assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Less derivative net assets classified as other current and long-term assets	(106)	(202)
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash	3,877	3,624
Fair Value, Measurements, Nonrecurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Common and preferred stock measured at fair value on a nonrecurring basis	1,017	1,073
Other investments measured at fair value on a nonrecurring basis	$ 564	$ 523