Financial Data By Segment (Tables)

12 Months Ended

Jun. 30, 2019

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment [Table Text Block]

	Employer Services		PEO Services		Other			Total
Year ended June 30, 2019
Revenues	$	9,942.8	$	4,242.7	$	(10.3	)	$	14,175.2
Earnings before income taxes	2,957.0		620.1		(571.5		)	3,005.6
Assets	34,606.3		1,584.1		5,697.3			41,887.7
Capital expenditures	98.2		—		64.5			162.7
Depreciation and amortization	321.0		3.5		84.5			409.0
Year ended June 30, 2018
Revenues	$	9,454.8	$	3,882.3	$	(9.4	)	$	13,327.7
Earnings before income taxes	2,598.1		544.6		(860.1		)	2,282.6
Assets	31,984.2		1,329.8		5,535.1			38,849.1
Capital expenditures	113.9		—		78.0			191.9
Depreciation and amortization	291.9		3.0		82.7			377.6
Year ended June 30, 2017
Revenues	$	8,914.2	$	3,468.4	$	(10.6	)	$	12,372.0
Earnings before income taxes	2,396.8		463.4		(243.3		)	2,616.9
Assets	31,724.3		1,160.4		6,002.2			38,886.9
Capital expenditures	83.0		0.2		165.8			249.0
Depreciation and amortization	247.3		1.3		67.5			316.1

Schedule of Revenue from External Customers and Long-Lived Assets, by Geographical Areas [Table Text Block]

	United States		Europe		Canada		Other		Total
Year ended June 30, 2019
Revenues	$	12,327.6	$	1,236.8	$	326.6	$	284.2	$	14,175.2
Assets	$	36,508.3	$	2,807.9	$	1,950.5	$	621.0	$	41,887.7
Year ended June 30, 2018
Revenues	$	11,493.3	$	1,242.2	$	321.6	$	270.6	$	13,327.7
Assets	$	33,586.6	$	2,608.6	$	2,073.1	$	580.8	$	38,849.1
Year ended June 30, 2017
Revenues	$	10,753.4	$	1,086.4	$	290.9	$	241.3	$	12,372.0
Assets	$	33,752.7	$	2,510.5	$	2,068.6	$	555.1	$	38,886.9