Stock-Based Compensation, Stock-based Comp Expense (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Stock-Based Compensation
Expense incurred for stock-based compensation plans	$ 16.6	$ 14.4	$ 46.4	$ 40.4
Recognized tax benefit related to stock-based compensation	3.6	8.9	27.1	19.7
Excess tax benefit from option exercises	$ 1.6	$ 7.0	$ 21.3	$ 14.1

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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