Schedule of Share Based Compensation Stock Options (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Intrinsic Value of Stock Options Exercised	$ 48.0	$ 91.5	$ 49.0
Stock Compensation Expense Related to Stock Option Awards	$ 15.7	$ 14.4	$ 14.8
Issued Stock Options	2.1	2.1	2.2
Weighted Average Fair Value of Stock Options issued (per share)	$ 12.90	$ 7.57	$ 6.85
Fair Value of Stock Options Issued	$ 27.8	$ 16.1	$ 15.3

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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.

+ References

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-Publisher FASB
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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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