Stock-Based Compensation, Stock-based Comp Expense (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Stock-Based Compensation
Expense incurred for stock-based compensation plans	$ 21.2	$ 19.0	$ 60.2	$ 51.0
Recognized tax benefit related to stock-based compensation	14.0	12.7	40.4	33.8
Excess tax benefit from option exercises	$ 12.3	$ 10.7	$ 34.3	$ 28.1

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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