v3.26.1
POSTRETIREMENT BENEFITS AND EMPLOYEE STOCK OWNERSHIP PLAN - Fair Value Of Plan Asset (Details) - USD ($)
$ in Millions
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2024
Pension Benefits      
ASSETS AT FAIR VALUE      
TOTAL ASSETS AT FAIR VALUE $ 12,159 $ 11,672 $ 10,857
Pension Benefits | Fair Value, Inputs, Level 1, 2 and 3      
ASSETS AT FAIR VALUE      
TOTAL ASSETS AT FAIR VALUE 2,831 1,312  
Pension Benefits | Fair Value Measured at Net Asset Value Per Share      
ASSETS AT FAIR VALUE      
TOTAL ASSETS AT FAIR VALUE 9,328 10,361  
Pension Benefits | Cash | Fair Value, Inputs, Level 1      
ASSETS AT FAIR VALUE      
TOTAL ASSETS AT FAIR VALUE 74 55  
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 2,519 1,050  
Pension Benefits | Insurance contracts | Fair Value, Inputs, Level 3      
ASSETS AT FAIR VALUE      
TOTAL ASSETS AT FAIR VALUE 238 207  
Other Retiree Benefits      
ASSETS AT FAIR VALUE      
TOTAL ASSETS AT FAIR VALUE 7,166 7,787 $ 8,043
Other Retiree Benefits | Fair Value, Inputs, Level 1, 2 and 3      
ASSETS AT FAIR VALUE      
TOTAL ASSETS AT FAIR VALUE 7,115 7,718  
Other Retiree Benefits | Fair Value Measured at Net Asset Value Per Share      
ASSETS AT FAIR VALUE      
TOTAL ASSETS AT FAIR VALUE 50 68  
Other Retiree Benefits | Cash | Fair Value, Inputs, Level 1      
ASSETS AT FAIR VALUE      
TOTAL ASSETS AT FAIR VALUE 180 135  
Other Retiree Benefits | Company common stock | Fair Value, Inputs, Level 1      
ASSETS AT FAIR VALUE      
TOTAL ASSETS AT FAIR VALUE 502 496  
Other Retiree Benefits | Company preferred stock | Fair Value, Inputs, Level 2      
ASSETS AT FAIR VALUE      
TOTAL ASSETS AT FAIR VALUE 6,433 7,087  
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