Financial Instruments (Summary of Estimated Fair Value of Long-term Obligations and Other Short-term Borrowings) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Jun. 30, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount of Long-Term and other Short-Term Borrowings	$ 6,775	$ 8,031
Carrying amount	6,775	8,031
Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value	$ 7,273	8,065
Interest Rate Swaps | Designated as Hedging Instrument | Fair Value Hedging
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives, Hedge Discontinuances, Termination of Hedging Instrument, Amount		$ 163