Stock-Based Compensation (Stock Appreciation Rights Outstanding and Exercisable) (Details) - Stock Appreciation Rights [Member] - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock Appreciation Rights Outstanding, Shares	1.3	1.5
Stock Appreciation Rights Exercisable, Shares	0.9
$34.06 to $46.78 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices per Share, lower range limit	$ 34.06
Range of Exercise Prices per Share, upper range limit	$ 46.78
Stock Appreciation Rights Outstanding, Shares	0.4
Stock Appreciation Rights Outstanding, Weighted-Average Remaining Contractual Term (in years)	2 years 3 months 29 days
Stock Appreciation Rights Outstanding, Aggregate Intrinsic Value	$ 35.2
Stock Appreciation Rights Exercisable, Shares	0.4
Stock Appreciation Rights Exercisable, Weighted-Average Remaining Contractual Life (in years)	2 years 3 months 29 days
Stock Appreciation Rights Exercisable, Aggregate Intrinsic Value	$ 35.2
$51.11 to $81.14 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices per Share, lower range limit	$ 51.11
Range of Exercise Prices per Share, upper range limit	$ 81.14
Stock Appreciation Rights Outstanding, Shares	0.5
Stock Appreciation Rights Outstanding, Weighted-Average Remaining Contractual Term (in years)	4 years 5 months 19 days
Stock Appreciation Rights Outstanding, Aggregate Intrinsic Value	$ 28.3
Stock Appreciation Rights Exercisable, Shares	0.4
Stock Appreciation Rights Exercisable, Weighted-Average Remaining Contractual Life (in years)	4 years 4 months 13 days
Stock Appreciation Rights Exercisable, Aggregate Intrinsic Value	$ 25.1
$92.64 to $126.31 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Range of Exercise Prices per Share, lower range limit	$ 92.64
Range of Exercise Prices per Share, upper range limit	$ 126.31
Stock Appreciation Rights Outstanding, Shares	0.4
Stock Appreciation Rights Outstanding, Weighted-Average Remaining Contractual Term (in years)	6 years
Stock Appreciation Rights Outstanding, Aggregate Intrinsic Value	$ 7.6
Stock Appreciation Rights Exercisable, Shares	0.1
Stock Appreciation Rights Exercisable, Weighted-Average Remaining Contractual Life (in years)	6 years
Stock Appreciation Rights Exercisable, Aggregate Intrinsic Value	$ 2.5