Corporate Investments and Funds Held For Clients (Narrative) (Details) - USD ($)	12 Months Ended
Jun. 30, 2021	Jun. 30, 2020
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	$ 24,371,700,000	$ 21,576,600,000
Client Fund Obligation repayment period	1 year
Client funds obligations	$ 34,403,800,000	25,831,600,000
Funds held for Clients Held-in Grantor Trust	$ 31,092,300,000
Client funds investments with original maturities (or less)	90 days
Percentage of the available-for-sale securities were rated AAA Or AA	72.00%
Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses	$ (77,600,000)	(700,000)
Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value	6,331,300,000	63,000,000.0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(100,000)	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,900,000	1,500,000
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(77,700,000)	(700,000)
Debt Securities, Available-for-sale, Unrealized Loss Position	6,333,200,000	64,500,000
Fair Value, Inputs, Level 1
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	0
Fair Value, Inputs, Level 3
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	0
Asset-Backed Auto Loan Receivables
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	1,247,400,000
Fixed Rate Credit Card
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	759,500,000
Asset-Backed Equipment Lease Receivable
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	263,500,000
Rate Reduction Receivable
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	68,700,000
Federal Farm Credit Banks
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	827,300,000
Federal Home Loan Banks
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	536,800,000
Commercial mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	834,600,000	868,200,000
Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses	0	0
Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value	16,700,000	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	1,500,000
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	16,700,000	1,500,000
Municipal Bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	569,500,000
Debt Security, Corporate, Non-US
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	237,500,000
Canadian provincial bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale	973,700,000	710,200,000
Securities in Unrealized Loss Position Less Than 12 Months, Gross Unrealized Losses	(5,300,000)	0
Securities in Unrealized Loss Position Less Than 12 Months, Fair Market Value	253,700,000	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	(5,300,000)	0
Debt Securities, Available-for-sale, Unrealized Loss Position	$ 253,700,000	$ 0

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Client Funds Held in Grantor Trust

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Client funds investments, maturity period.

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Represent the Company's contractual obligations to remit funds to satisfy clients' payroll and tax payment obligations and are recorded on the Balance Sheet at the time that the Company impounds funds from clients.

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Percentage of the available-for-sale securities were rated AAA or AA

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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