RISK MANAGEMENT ACTIVITIES AND FAIR VALUE MEASUREMENTS - ADDITIONAL INFORMATION (Details) - USD ($) $ in Millions	Mar. 31, 2016	Jun. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	$ 24,266	$ 23,127
Long Term Debt, Current Maturities measured at Fair Value	2,641	2,776
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	2,328	2,180
U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis	201	700
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis	4,401	2,789
Corporate bond securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis	321	221
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis	$ 977	$ 1,052