Equity Incentive Plan Textuals (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
EQUITY INCENTIVE PLAN [Abstract]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	10 years 6 months
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 263.58	$ 244.90
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Intrinsic Value, Amount Per Share	$ 7,800,000	$ 7,200,000
Number of Shares Authorized for Stock Option Plan	2,000,000
Options, Award Vesting Period	5 years
Restricted Stock Units, Vesting Period	five
Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 77.64	$ 66.33	$ 46.72
Options, Exercises in Period, Total Intrinsic Value	$ 66.9	$ 60.0	$ 50.9
Stock Options, Vested in Period, Total Fair Value	6.4	5.7	6.9
Restricted Stock Units, Vested in Period, Total Fair Value	5.8	5.6	5.3
Allocated Share-based Compensation Expense for Restricted Stock Units	5.6	5.5
Number of Shares Available for Grant	2,588,311
Deferred Compensation Liability, Current and Noncurrent	$ 43.0
Estimated Weighted Average Amortization Period	2 years 3 months 18 days