Stock-Based Compensation, Stock-based Comp Expense (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Stock-Based Compensation
Expense incurred for stock-based compensation plans	$ 19.0	$ 16.6	$ 51.0	$ 46.4
Recognized tax benefit related to stock-based compensation	12.7	3.6	33.8	27.1
Excess tax benefit from option exercises	$ 10.7	$ 1.6	$ 28.1	$ 21.3

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

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Amount of tax benefit from exercise of option under share-based payment arrangement.

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