Short-term Financing - Commercial Paper Program and Reverse Repurchase Agreements (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2023	Dec. 31, 2022
Commercial paper program
Short-term Debt [Line Items]
Average outstanding balances	$ 3,900.0	$ 3,400.0	$ 4,000.0	$ 4,000.0
Weighted average interest rates	5.40%	3.50%	5.30%	2.80%
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	$ 2,423.3	$ 960.8	$ 1,901.1	$ 1,040.1
Weighted average interest rates	5.40%	3.40%	5.40%	2.90%