POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - Fair Value Of Plan Asset (Details) - USD ($) $ in Millions	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2022
Pension Benefits
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	$ 10,857	$ 10,374	$ 10,173
Pension Benefits | Fair Value, Inputs, Level 1, 2 and 3
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	1,508	1,337
Pension Benefits | Fair Value Measured at Net Asset Value Per Share
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	9,349	9,037
Pension Benefits | Cash | Fair Value, Inputs, Level 1
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	267	54
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	1,076	1,190
Pension Benefits | Insurance contracts | Fair Value, Inputs, Level 3
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	165	93
Other Retiree Benefits
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	8,043	7,324	$ 6,889
Other Retiree Benefits | Fair Value, Inputs, Level 1, 2 and 3
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	7,966	7,237
Other Retiree Benefits | Fair Value Measured at Net Asset Value Per Share
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	77	87
Other Retiree Benefits | Cash | Fair Value, Inputs, Level 1
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	135	148
Other Retiree Benefits | Company common stock | Fair Value, Inputs, Level 1
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	451	368
Other Retiree Benefits | Company preferred stock | Fair Value, Inputs, Level 2
ASSETS AT FAIR VALUE
TOTAL ASSETS AT FAIR VALUE	7,380	6,721
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