Consolidated Balance Sheets - USD ($) $ in Millions		Jun. 30, 2020		Jun. 30, 2019
Statement of Financial Position [Abstract]
Long-term Marketable Securities Under Reverse Repurchase Agreements		$ 13.6		$ 261.4
Current assets:
Cash and cash equivalents		1,908.5		1,949.2
Short-term marketable securities		0.0		10.5
Accounts receivable, net of allowance for doubtful accounts of $92.5 and $54.9, respectively		2,441.3		2,439.3
Other current assets		506.2		509.1
Total current assets before funds held for clients		4,856.0		4,908.1
Funds held for clients		26,708.1		29,434.2
Total current assets		31,564.1		34,342.3
Long-term receivables, net of allowance for doubtful accounts of $0.5 and $0.4, respectively		18.6		23.8
Property, plant and equipment, net		703.9		764.2
Operating lease right-of-use asset		493.7		0.0
Deferred contract costs	[1]	2,401.6		2,428.5
Other assets		458.4		934.4
Goodwill		2,309.4		2,323.0
Intangible assets, net		1,215.8		1,071.5
Total assets		39,165.5		41,887.7
Liabilities
Accounts payable		102.0		125.5
Accrued expenses and other current liabilities		1,980.7		1,759.0
Accrued payroll and payroll-related expenses		557.0		721.1
Dividends payable		387.3		340.1
Short-term deferred revenues		212.5		220.7
Obligations under reverse repurchase agreements (A)		13.6	[2]	262.0
Short-term debt		1,001.8		0.0
Income taxes payable		40.1		54.8
Total current liabilities before client funds obligations		4,295.0		3,483.2
Client funds obligations		25,831.6		29,144.5
Total current liabilities		30,126.6		32,627.7
Long-term debt		1,002.8		2,002.2
Operating lease liabilities				0.0
Other liabilities		837.0		798.7
Deferred income taxes		731.9		659.9
Long-term deferred revenues		370.6		399.3
Total liabilities		33,413.3		36,487.8
Stockholders' equity:
Preferred stock, $1.00 par value: Authorized, 0.3 shares; issued, none		0.0		0.0
Common Stock, Value, Issued		63.9		63.9
Capital in excess of par value		1,333.8		1,183.2
Retained earnings		18,436.3		17,500.6
Treasury Stock, Value		14,067.0		13,090.5
Accumulated other comprehensive loss		(14.8)		(257.3)
Total stockholders’ equity		5,752.2		5,399.9
Total liabilities and stockholders’ equity		$ 39,165.5		41,887.7
Cash And Cash Equivalents Under Reverse Repurchase Agreements				$ 0.6

[1] (1) The amount of total deferred costs amortized during the twelve months ended June 30, 2020, June 30, 2019, and June 30, 2018 were $915.0 million, $874.0 million, and $837.4 million, respectively.

[2] (A) As of June 30, 2020, $13.6 million of long-term marketable securities have been pledged as collateral under the Company's reverse repurchase agreements. As of June 30, 2019, $261.4 million of long-term marketable securities and $0.6 million of cash and cash equivalents have been pledged as collateral under the Company's reverse repurchase agreements (see Note 8).