Debt - Summary of Long-Term Debt (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2018	Jun. 30, 2018
Debt Instrument [Line Items]
Long-Term Debt	$ 18,081		$ 18,894
2.675% Notes due December 15, 2019
Debt Instrument [Line Items]
Interest rate	2.675%
Long-Term Debt	$ 0		1,123
2.404% Notes due June 5, 2020
Debt Instrument [Line Items]
Interest rate	2.404%
Long-Term Debt	$ 0		998
3.250% Notes due November 12, 2020
Debt Instrument [Line Items]
Interest rate	3.25%
Long-Term Debt	$ 699		699
Floating Rate Notes due December 29, 2020
Debt Instrument [Line Items]
Long-Term Debt	$ 748		996
0.174% Notes due June 4, 2021
Debt Instrument [Line Items]
Interest rate	0.174%	0.174%
Long-Term Debt	$ 651		0
3.125% Notes due November 8, 2021
Debt Instrument [Line Items]
Interest rate	3.125%
Long-Term Debt	$ 1,004		990
2.894% Notes due June 6, 2022
Debt Instrument [Line Items]
Interest rate	2.894%
Long-Term Debt	$ 1,795		1,793
Floating Rate Notes due June 6, 2022
Debt Instrument [Line Items]
Long-Term Debt	$ 498		498
1.000% Notes due December 15, 2022
Debt Instrument [Line Items]
Interest rate	1.00%
Long-Term Debt	$ 542		576
Revolving Credit Facility
Debt Instrument [Line Items]
Long-Term Debt	$ 480		0
3.300% Notes due March 1, 2023
Debt Instrument [Line Items]
Interest rate	3.30%
Long-Term Debt	$ 295		296
1.401% Notes due May 24, 2023
Debt Instrument [Line Items]
Interest rate	1.401%			1.401%
Long-Term Debt	$ 325		346
0.632% Notes due June 4, 2023
Debt Instrument [Line Items]
Interest rate	0.632%	0.632%
Long-Term Debt	$ 867		0
3.875% Notes due May 15, 2024
Debt Instrument [Line Items]
Interest rate	3.875%
Long-Term Debt	$ 181		182
3.363% Notes due June 6, 2024
Debt Instrument [Line Items]
Interest rate	3.363%
Long-Term Debt	$ 1,740		1,738
3.734% Notes due December 15, 2024
Debt Instrument [Line Items]
Interest rate	3.734%
Long-Term Debt	$ 1,369		1,368
3.020% Notes due May 24, 2025
Debt Instrument [Line Items]
Interest rate	3.02%			3.02%
Long-Term Debt	$ 306		324
1.208% Notes due June 4, 2026
Debt Instrument [Line Items]
Interest rate	1.208%	1.208%
Long-Term Debt	$ 649		0
6.700% Notes due December 1, 2026
Debt Instrument [Line Items]
Interest rate	6.70%
Long-Term Debt	$ 174		177
1.900% Notes due December 15, 2026
Debt Instrument [Line Items]
Interest rate	1.90%
Long-Term Debt	$ 541		575
3.700% Notes due June 6, 2027
Debt Instrument [Line Items]
Interest rate	3.70%	3.70%
Long-Term Debt	$ 1,714		2,383
7.000% Debentures due August 1, 2027
Debt Instrument [Line Items]
Interest rate	7.00%
Long-Term Debt	$ 175		156
6.700% Debentures due August 1, 2028
Debt Instrument [Line Items]
Interest rate	6.70%
Long-Term Debt	$ 175		154
6.000% Notes due May 15, 2039
Debt Instrument [Line Items]
Interest rate	6.00%
Long-Term Debt	$ 246		246
5.000% Notes due November 12, 2040
Debt Instrument [Line Items]
Interest rate	5.00%
Long-Term Debt	$ 124		296
4.875% Notes due May 15, 2044
Debt Instrument [Line Items]
Interest rate	4.875%	4.875%
Long-Term Debt	$ 248		331
4.685% Notes due December 15, 2044
Debt Instrument [Line Items]
Interest rate	4.685%	4.685%
Long-Term Debt	$ 1,045		1,159
4.669% Notes due June 6, 2047
Debt Instrument [Line Items]
Interest rate	4.669%
Long-Term Debt	$ 1,485		1,484
Other long-term debt
Debt Instrument [Line Items]
Long-Term Debt	$ 5		$ 8