Business Combinations - Pro Forma Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2019
Summary of unaudited consolidated pro forma results of operations
Revenues	$ 6,017.1	$ 17,899.2
Income from continuing operations	115.5	320.0
Net income	$ 115.7	$ 320.4
Income from continuing operations per diluted common share (in dollars per share)	$ 1.41	$ 3.86
Net income per diluted common share (in dollars per share)	$ 1.42	$ 3.86

The pro forma diluted net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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Per diluted share amount of pro forma income from continuing operations, after tax, as if the business combination had been completed at the beginning of a period.

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Amount after tax of pro forma income from continuing operations as if the business combination had been completed at the beginning of a period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
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-Paragraph 2
-Subparagraph (h)(2)
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-Topic 805
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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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