Short-term Financing - Commercial Paper Program and Reverse Repurchase Agreements (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Commercial paper program
Short-term Debt [Line Items]
Average outstanding balances	$ 700.0	$ 1,200.0	$ 1,600.0	$ 2,900.0
Weighted average interest rates	0.10%	1.50%	0.10%	1.90%
Weighted average maturity (approximately in days)	1 day	1 day	1 day	2 days
Reverse repurchase agreements
Short-term Debt [Line Items]
Average outstanding balances	$ 54.9	$ 123.2	$ 97.1	$ 295.9
Weighted average interest rates	0.20%	1.60%	0.30%	1.80%