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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Equity Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Exercises in Period, Total Intrinsic Value	$ 41.4	$ 26.2	$ 17.0
Performance Contingent Unit Share Payout	0.40	0.820
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	1 year 7 months
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 29.7
Performance Contingent Units Measurement Period	3 years
Allocated Share-based Compensation Expense	$ 33.1	$ 16.0	$ 24.4
Options, Grants in Period, Weighted Average Exercise Price	$ 93.53	$ 91.65	$ 78.48
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	577,071,000
Expiration Period	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	329,345,000
Options, Grants in Period, Weighted Average Exercise Price	$ 93.53
Flexible Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Of Shares Available For Grant	13,360,077
Flexible Stock Plan For Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number Of Shares Available For Grant	212,500
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	94,436	192,725
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	206,550
Options, Grants in Period, Weighted Average Exercise Price	$ 93.53
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	28,995
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Period	1 year
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Period	5 years