POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 1991	Jun. 30, 1989
Defined Benefit Plan Disclosure [Line Items]
Defined contribution expense	$ 425	$ 392	$ 366
Accumulated benefit obligation	$ 11,600	$ 11,800
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets (in percent)	6.00%	5.90%	5.50%
Expected future employer contributions, next fiscal year	$ 180
Pension Benefits | Series A Preferred Stock
Defined Benefit Plan Disclosure [Line Items]
ESOP, direct loan amount					$ 1,000
ESOP, debt structure, employer loan guarantee	$ 0
Dividend (in dollars per share)	$ 3.83
Liquidation value (in dollars per share)	$ 6.82
Other Retiree Benefits
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets (in percent)	8.50%	8.40%	8.40%
Expected future employer contributions, next fiscal year	$ 53
Other Retiree Benefits | Series B Preferred Stock
Defined Benefit Plan Disclosure [Line Items]
ESOP, direct loan amount				$ 1,000
ESOP, debt structure, employer loan guarantee	$ 737
Dividend (in dollars per share)	$ 3.83
Liquidation value (in dollars per share)	$ 12.96
Treasury Stock
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets (in percent)	8.50%
Minimum | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets (in percent)	8.00%
Minimum | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets (in percent)	3.00%
Maximum | Equity securities
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets (in percent)	9.00%
Maximum | Debt securities
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets (in percent)	5.00%
United States
Defined Benefit Plan Disclosure [Line Items]
Contribution rate (in percent)	13.00%	13.00%	14.00%