Stock-Based Compensation Plans (Summary Of Restricted Stock Units Activity) (Details) - Restricted Stock Units (RSUs) [Member] - USD ($) $ / shares in Units, $ in Millions		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, as of December 31		862,682
Granted		1,500
Converted		(1,348)
Forfeited		(3,415)
Outstanding, as of December 31		859,419	[1]	862,682
Vested		532,160
Weighted Average Grant-Date Fair Value Per Share, Outstanding as of December 31		$ 61.93
Weighted Average Grant-Date Fair Value Per Share, Nonvested, Granted		139.00		$ 130.16	$ 122.81
Weighted Average Grant-Date Fair Value Per Share, Nonvested, Converted		119.33
Weighted Average Grant-Date Fair Value Per Share, Nonvested, Forfeited		122.81
Weighted Average Grant-Date Fair Value Per Share, Outstanding as of December 31		61.73		$ 61.93
Weighted Average Grant-Date Fair Value Per Share, Vested as of December 31		$ 33.74
Aggregate Intrinsic Value, Outstanding	[2]	$ 183.9
Aggregate Intrinsic Value, Vested	[2]	$ 113.9
Weighted Average Remaining Contractual Term, Outstanding		3 years 11 months
Weighted Average Remaining Contractual Term, Vested		1 year 4 months

[1] No RSUs outstanding at December 31, 2015 were convertible to shares of common stock.

[2] The intrinsic value of RSUs is measured by applying the closing stock price as of December 31, 2015 to the applicable number of units.