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		6 Months Ended
	Nov. 30, 2018	Nov. 30, 2017	Nov. 30, 2018	Nov. 30, 2017
JPM $1 Billion Credit Facility [Member] \| JP Morgan Chase Bank, N.A. [Member]
Line of Credit Facility [Line Items]
Number of days borrowed	4 days	6 days	10 days	19 days
Maximum amount borrowed	$ 483.0	$ 700.0	$ 483.0	$ 700.0
Weighted-average amount borrowed	$ 389.8	$ 445.8	$ 285.7	$ 331.6
Weighted-average interest rate	5.12%	4.25%	5.06%	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	3 days	20 days	7 days	20 days
Maximum amount borrowed	$ 135.5	$ 400.0	$ 223.0	$ 400.0
Weighted-average amount borrowed	$ 83.0	$ 215.8	$ 111.8	$ 215.8
Weighted-average interest rate	5.25%	2.84%	5.07%	2.84%
PNC $150 Million Credit Facility [Member] \| PNC Bank, National Association [Member]
Line of Credit Facility [Line Items]
Number of days borrowed	91 days	91 days	179 days	179 days
Maximum amount borrowed	$ 57.7	$ 58.6	$ 57.7	$ 58.6
Weighted-average amount borrowed	$ 57.3	$ 57.8	$ 56.6	$ 56.8
Weighted-average interest rate	2.68%	1.78%	2.61%	1.73%