Goodwill and Other Intangible Assets (Pro Forma Financial Information and Acquisition Results) (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Combinations [Abstract]
Business combinations, unaudited supplemental pro forma revenue	$ 6,400.0	$ 7,600.0	$ 7,400.0
Business combinations, unaudited supplemental pro forma net income	334.5	406.6	258.7
Business combinations, consolidated acquisition-related revenue	229.9	188.3	154.4
Business combinations, consolidated acquisition-related net income	$ (6.7)	$ (1.4)	$ 1.4

The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(3)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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