Paychex, Inc. Quarterly report pursuant to Section 13 or 15(d)

Funds Held for Clients and Corporate Investments (Narrative) (Details)

Funds Held for Clients and Corporate Investments (Narrative) (Details) $ in Millions		9 Months Ended
	Feb. 28, 2021 USD ($) security	Feb. 28, 2021 USD ($) security	May 31, 2020 USD ($) security
Schedule of Available-for-sale Securities [Line Items]
Net unrealized gains on available-for-sale securities	$ 82.1	$ 82.1	$ 100.0
Number of available-for-sale securities in an unrealized loss position \| security	163	163	19
Percentage of available-for-sale securities in an unrealized loss position	13.00%	13.00%	2.00%
Gross unrealized losses on available-for-sale securities	$ 4.4	$ 4.4	$ 1.7
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses on available-for-sale securities	$ 0.2	0.2	0.1
Corporate Bonds [Member] \| Minimum [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities maturity date	Mar. 01, 2021
Corporate Bonds [Member] \| Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities maturity date	Feb. 08, 2028
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses on available-for-sale securities	$ 2.9	$ 2.9	$ 1.6
Municipal Bonds [Member] \| Minimum [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities maturity date	Mar. 01, 2021
Municipal Bonds [Member] \| Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities maturity date	Mar. 01, 2028
VRDNs [Member] \| Minimum [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities contractual maturities		20 years
VRDNs [Member] \| Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale securities contractual maturities		30 years