Customer Funds - Amortized Cost and Fair Value of Investment Security Available for Sale (Detail) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Investments Debt And Equity Securities [Abstract]
Due in one year or less, Cost	$ 5,660.9
Due in one to three years, Cost	702.4
Due in three to five years, Cost	754.1
Due after five years, Cost	288.9
Invested customer funds, Cost	7,406.3	$ 3,501.5
Due in one year or less, Fair Value	5,662.4
Due in one to three years, Fair Value	694.8
Due in three to five years, Fair Value	716.8
Due after five years, Fair Value	276.2
Invested customer funds, Fair Value	$ 7,350.2	$ 3,514.8

Available For Sale Securities Debt Maturities After Five Years Amortized Cost

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Available For Sale Securities Debt Maturities After Five Years Fair Value

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- Definition

Available For Sale Securities Debt Maturities After One Through Three Years Amortized Cost

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Available For Sale Securities Debt Maturities After One Through Three Years Fair Value

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Available For Sale Securities Debt Maturities After Three Through Five Years Amortized Cost

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Available For Sale Securities Debt Maturities After Three Through Five Years Fair Value

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Invested customer funds amortized cost.

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Invested customer funds fair value.

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27198-111563

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Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 320
-Section 50
-Paragraph 3A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123599081&loc=SL120269850-112803

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27198-111563

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27161-111563

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