POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - Fair Value Of Plan Asset (Details) - USD ($) $ in Millions	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2023
Pension Benefits
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	$ 11,672	$ 10,857	$ 10,374
Pension Benefits | Fair Value, Inputs, Level 1, 2 and 3
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	1,312	1,508
Pension Benefits | Fair Value Measured at Net Asset Value Per Share
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	10,361	9,349
Pension Benefits | Cash | Fair Value, Inputs, Level 1
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	55	267
Pension Benefits | Company common stock | Fair Value, Inputs, Level 1
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	0	0
Pension Benefits | Company preferred stock | Fair Value, Inputs, Level 2
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	0	0
Pension Benefits | Fixed income securities | Fair Value, Inputs, Level 2
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	1,050	1,076
Pension Benefits | Insurance contracts | Fair Value, Inputs, Level 3
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	207	165
Other Retiree Benefits
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	7,787	8,043	$ 7,324
Other Retiree Benefits | Fair Value, Inputs, Level 1, 2 and 3
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	7,718	7,966
Other Retiree Benefits | Fair Value Measured at Net Asset Value Per Share
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	68	77
Other Retiree Benefits | Cash | Fair Value, Inputs, Level 1
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	135	135
Other Retiree Benefits | Company common stock | Fair Value, Inputs, Level 1
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	496	451
Other Retiree Benefits | Company preferred stock | Fair Value, Inputs, Level 2
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	7,087	7,380
Other Retiree Benefits | Fixed income securities | Fair Value, Inputs, Level 2
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	0	0
Other Retiree Benefits | Insurance contracts | Fair Value, Inputs, Level 3
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	$ 0	$ 0