Stock-Based Compensation, Stock-based Comp Expense (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Stock-Based Compensation
Expense incurred for stock-based compensation plans	$ 14.4	$ 12.6	$ 40.4	$ 37.1
Recognized tax benefit related to stock-based compensation	8.9	19.5	19.7	54.7
Excess tax benefit from option exercises	$ 7.0	$ 16.6	$ 14.1	$ 45.8

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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-Name Accounting Standards Codification
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- Definition

The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

+ References

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- Definition

Amount of tax benefit from exercise of stock options granted under share-based compensation arrangement.

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