Stock-Based Compensation, Stock-based Comp Expense (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Stock-Based Compensation
Expense incurred for stock-based compensation plans	$ 16.6	$ 15.4	$ 32.0	$ 29.8
Recognized tax benefit related to stock-based compensation	14.3	14.9	21.1	23.5
Excess tax benefit from option exercises	$ 12.4	$ 12.9	$ 17.4	$ 19.7

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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