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

Short-term Financing (Credit Facility Amount Borrowed) (Details) - Revolving Credit Facility [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018
JPM $1 Billion Credit Facility [Member] \| JP Morgan Chase Bank, N.A. [Member]
Line of Credit Facility [Line Items]
Number of days borrowed	71 days	2 days	81 days	21 days
Maximum amount borrowed	$ 400.0	$ 200.0	$ 483.0	$ 700.0
Weighted-average amount borrowed	$ 400.0	$ 125.0	$ 385.9	$ 311.9
Weighted-average interest rate	3.48%	4.25%	3.66%	4.24%
JPM $500 Million Credit Facility [Member] \| JP Morgan Chase Bank, N.A. [Member]
Line of Credit Facility [Line Items]
Number of days borrowed	71 days	19 days	78 days	39 days
Maximum amount borrowed	$ 400.0	$ 75.0	$ 400.0	$ 400.0
Weighted-average amount borrowed	$ 400.0	$ 75.0	$ 374.1	$ 147.2
Weighted-average interest rate	3.48%	2.19%	3.57%	2.69%
PNC $150 Million Credit Facility [Member] \| PNC Bank, National Association [Member]
Line of Credit Facility [Line Items]
Number of days borrowed	90 days	90 days	269 days	269 days
Maximum amount borrowed	$ 58.9	$ 59.9	$ 58.9	$ 59.9
Weighted-average amount borrowed	$ 57.7	$ 59.1	$ 57.0	$ 57.6
Weighted-average interest rate	2.94%	2.01%	2.72%	1.83%