Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Income Taxes [Line Items]
Provision (benefit) for income taxes					$ 4,448	$ 19,903	$ 4,412
Income taxes paid, net of refunds					8,400	5,500	2,400
Gross unrecognized tax benefits related to uncertain tax positions	$ 13,146		$ 11,961		13,146	11,961	11,737	$ 10,164
Gross unrecognized tax benefits related to uncertain tax positions, if recognized would affect our effective tax rates	12,000		11,300		12,000	11,300	10,200
Accrued interest expense related to uncertain tax positions net of federal income tax benefits	3,400		3,000		3,400	3,000	2,300
Interest expense related to uncertain tax positions, net of income tax benefits					515	688	$ 399
Transfer of Intangible Properties
Income Taxes [Line Items]
Provision (benefit) for income taxes	(2,600)				(2,600)
Tax Cuts and Jobs Act
Income Taxes [Line Items]
Provision (benefit) for income taxes		$ 157	$ (104)	$ 13,800	$ 157	13,700
Charge related to transition tax						17,900
Benefit from impact of changes in tax rate						$ 4,200
Regional Operating Centers
Income Taxes [Line Items]
Foreign earnings, taxed at rates lower than U.S. rate as a percentage of foreign income before tax					82.00%	87.00%	76.00%
Federal
Income Taxes [Line Items]
Operating loss carryforwards	978				$ 978
Foreign Country
Income Taxes [Line Items]
Operating loss carryforwards	11,600				11,600
State
Income Taxes [Line Items]
Operating loss carryforwards	$ 770				$ 770
Federal and State | Earliest Tax Year
Income Taxes [Line Items]
Operating loss carryforwards expiration year					2020
Federal and State | Latest Tax Year
Income Taxes [Line Items]
Operating loss carryforwards expiration year					2039