Investment Components, Including Associated Derivatives (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	$ 136,160	$ 119,078
Unrealized Gains	3,267	4,895
Unrealized Losses	(423)	(302)
Recorded Basis	139,004	123,671
Cash and cash equivalents	7,663	6,510	$ 5,595	$ 8,669
Short-term Investments	125,318	106,730
Equity and Other Investments	6,023	10,431
Cash
Cash, Cash Equivalents and Investments [Line Items]
Cash	3,624	3,501
Unrealized Gains	0	0
Unrealized Losses	0	0
Cash and cash equivalents	3,624	3,501
Short-term Investments	0	0
Equity and Other Investments	0	0
Mutual funds
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	1,478	1,012
Unrealized Gains	0	0
Unrealized Losses	0	0
Recorded Basis	1,478	1,012
Cash and cash equivalents	1,478	1,012
Short-term Investments	0	0
Equity and Other Investments	0	0
Commercial paper
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	319	298
Unrealized Gains	0	0
Unrealized Losses	0	0
Recorded Basis	319	298
Cash and cash equivalents	69	298
Short-term Investments	250	0
Equity and Other Investments	0	0
Certificates of deposit
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	1,358	1,000
Unrealized Gains	0	0
Unrealized Losses	0	0
Recorded Basis	1,358	1,000
Cash and cash equivalents	972	868
Short-term Investments	386	132
Equity and Other Investments	0	0
U.S. government and agency securities
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	112,119	89,970
Unrealized Gains	85	245
Unrealized Losses	(360)	(11)
Recorded Basis	111,844	90,204
Cash and cash equivalents	16	100
Short-term Investments	111,828	90,104
Equity and Other Investments	0	0
Foreign government bonds
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	5,276	5,502
Unrealized Gains	2	10
Unrealized Losses	(13)	(18)
Recorded Basis	5,265	5,494
Cash and cash equivalents	1,504	731
Short-term Investments	3,761	4,763
Equity and Other Investments	0	0
Mortgage- and asset-backed securities
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	3,921	4,789
Unrealized Gains	14	21
Unrealized Losses	(4)	(2)
Recorded Basis	3,931	4,808
Cash and cash equivalents	0	0
Short-term Investments	3,931	4,808
Equity and Other Investments	0	0
Corporate notes and bonds
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	4,786	6,509
Unrealized Gains	61	110
Unrealized Losses	(12)	(35)
Recorded Basis	4,835	6,584
Cash and cash equivalents	0	0
Short-term Investments	4,835	6,584
Equity and Other Investments	0	0
Municipal securities
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	284	285
Unrealized Gains	43	57
Unrealized Losses	0	0
Recorded Basis	327	342
Cash and cash equivalents	0	0
Short-term Investments	327	342
Equity and Other Investments	0	0
Common and preferred stock
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	2,472	5,597
Unrealized Gains	3,062	4,452
Unrealized Losses	(34)	(236)
Recorded Basis	5,500	9,813
Cash and cash equivalents	0	0
Short-term Investments	0	0
Equity and Other Investments	5,500	9,813
Other investments
Cash, Cash Equivalents and Investments [Line Items]
Cost Basis	523	615
Unrealized Gains	0	0
Unrealized Losses	0	0
Recorded Basis	523	615
Cash and cash equivalents	0	0
Short-term Investments	0	(3)
Equity and Other Investments	$ 523	$ 618