Risk Management Activities and Fair Value Measurements - Notional Amounts And Fair Values Of Qualifying And Non-Qualifying Financial Instruments Used In Hedging Transactions (Details) - USD ($) $ in Millions	Dec. 31, 2024	Jun. 30, 2024
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	$ 19,326	$ 16,325
Fair Value Asset	546	120
Fair Value (Liability)	(255)	(379)
Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	15,968	13,133
Fair Value Asset	545	119
Fair Value (Liability)	(215)	(356)
Interest rate contracts | Fair Value Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	2,914	2,993
Fair Value Asset	0	0
Fair Value (Liability)	(215)	(325)
Foreign currency interest rate contracts | Not Designated as Hedging Instrument
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	3,359	3,192
Fair Value Asset	1	1
Fair Value (Liability)	(40)	(23)
Foreign currency interest rate contracts | Net Investment Hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional Amount	13,054	10,140
Fair Value Asset	545	119
Fair Value (Liability)	$ 0	$ (31)