Investment Components, Including Associated Derivatives (Detail) - USD ($) $ in Millions	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	$ 136,667	$ 136,160
Unrealized Gains	220	3,267
Unrealized Losses	(1,257)	(423)
Recorded Basis	135,630	139,004
Cash and cash equivalents	11,946	7,663	$ 6,510	$ 5,595
Short-term Investments	121,822	125,318
Equity and Other Investments	1,862	6,023
Cash
Cash, Cash Equivalents and Investments [Line Items]
Cash	3,942	3,624
Unrealized Gains	0	0
Unrealized Losses	0	0
Cash and cash equivalents	3,942	3,624
Short-term Investments	0	0
Equity and Other Investments	0	0
Mutual funds
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	246	1,478
Unrealized Gains	0	0
Unrealized Losses	0	0
Recorded Basis	246	1,478
Cash and cash equivalents	246	1,478
Short-term Investments	0	0
Equity and Other Investments	0	0
Commercial paper
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	2,513	319
Unrealized Gains	0	0
Unrealized Losses	0	0
Recorded Basis	2,513	319
Cash and cash equivalents	2,215	69
Short-term Investments	298	250
Equity and Other Investments	0	0
Certificates of deposit
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	2,058	1,358
Unrealized Gains	0	0
Unrealized Losses	0	0
Recorded Basis	2,058	1,358
Cash and cash equivalents	1,865	972
Short-term Investments	193	386
Equity and Other Investments	0	0
U.S. government and agency securities
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	109,862	112,119
Unrealized Gains	62	85
Unrealized Losses	(1,167)	(360)
Recorded Basis	108,757	111,844
Cash and cash equivalents	3,678	16
Short-term Investments	105,079	111,828
Equity and Other Investments	0	0
Foreign government bonds
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	5,182	5,276
Unrealized Gains	1	2
Unrealized Losses	(10)	(13)
Recorded Basis	5,173	5,265
Cash and cash equivalents	0	1,504
Short-term Investments	5,173	3,761
Equity and Other Investments	0	0
Mortgage- and asset-backed securities
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	3,868	3,921
Unrealized Gains	4	14
Unrealized Losses	(13)	(4)
Recorded Basis	3,859	3,931
Cash and cash equivalents	0	0
Short-term Investments	3,859	3,931
Equity and Other Investments	0	0
Corporate notes and bonds
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	6,947	4,786
Unrealized Gains	21	61
Unrealized Losses	(56)	(12)
Recorded Basis	6,912	4,835
Cash and cash equivalents	0	0
Short-term Investments	6,912	4,835
Equity and Other Investments	0	0
Municipal securities
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	271	284
Unrealized Gains	37	43
Unrealized Losses	(1)	0
Recorded Basis	307	327
Cash and cash equivalents	0	0
Short-term Investments	307	327
Equity and Other Investments	0	0
Common and preferred stock
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	1,220	2,472
Unrealized Gains	95	3,062
Unrealized Losses	(10)	(34)
Recorded Basis	1,305	5,500
Cash and cash equivalents	0	0
Short-term Investments	0	0
Equity and Other Investments	1,305	5,500
Other investments
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	558	523
Unrealized Gains	0	0
Unrealized Losses	0	0
Recorded Basis	558	523
Cash and cash equivalents	0	0
Short-term Investments	1	0
Equity and Other Investments	$ 557	$ 523