Short-term Financing - Commercial Paper Program and Reverse Repurchase Agreements (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Commercial paper program
Short-term Debt [Line Items]
Average outstanding balances	$ 1,900.0	$ 1,800.0	$ 1,900.0	$ 2,100.0
Weighted average interest rates	0.10%	0.10%	0.10%	0.10%
Weighted average maturity (approximately in days)	1 day	1 day	1 day	1 day
Reverse repurchase agreements
Short-term Debt [Line Items]
Average outstanding balances	$ 228.4	$ 83.2	$ 211.7	$ 117.8
Weighted average interest rates	0.20%	0.30%	0.20%	0.30%