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Equity Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Allocated Share-based Compensation Expense	$ 16.0	$ 24.4	$ 20.3
Options, Exercises in Period, Total Intrinsic Value	$ 26.2	$ 17.0	$ 11.3
Performance Contingent Units Measurement Period	3 years
Performance Contingent Unit Share Payout	0.8203	0.529
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 30.5
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	2 years 1 month
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Grants in Period, Weighted Average Exercise Price	$ 91.65	$ 78.48	$ 58.77
Stock Options [Member]
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	652,015,000
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration Period	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	506,344,000
Options, Grants in Period, Weighted Average Exercise Price	$ 91.65
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]
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	192,725	103,358
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	185,783
Options, Grants in Period, Weighted Average Exercise Price	$ 90.15
Restricted Stock Units (RSUs) [Member]
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	0
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	37,078
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