Short-term Financing - Commercial Paper Program and Reverse Repurchase Agreements (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2025	Mar. 31, 2024	Mar. 31, 2025	Mar. 31, 2024
Commercial paper program
Short-term Debt [Line Items]
Average outstanding balances (in billions)	$ 3,300.0	$ 2,700.0	$ 4,200.0	$ 3,600.0
Weighted average interest rates	4.40%	5.40%	4.90%	5.30%
Weighted average maturity (approximately in days)	2 days	2 days	2 days	2 days
Reverse repurchase agreements
Short-term Debt [Line Items]
Average outstanding balances (in billions)	$ 900.0	$ 600.0	$ 2,800.0	$ 1,500.0
Weighted average interest rates	4.10%	5.40%	4.90%	5.40%