Schedule of Share Based Compensation Stock Options (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Intrinsic Value of Stock Options Exercised	$ 15.2	$ 7.5	$ 45.2	$ 34.7
Stock Compensation Expense Related to Stock Option Awards	$ 12.3	$ 9.0	$ 15.0	$ 10.7
Issued Stock Options	1.9	1.8	1.9	1.8
Weighted Average Fair Value of Stock Options issued (per share)	$ 9.63	$ 9.70	$ 9.63	$ 9.67
Fair Value of Stock Options Issued	$ 18.0	$ 17.1	$ 18.1	$ 17.5

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Net number of share options (or share units) granted during the period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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The fair value of stock issued in noncash financing activities.

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The noncash expense that accounts for the value of stock or unit options distributed to employees as compensation.

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