Share-Based Compensation and Benefit Plans (Stock Option Activity) (Details) (Stock Option [Member], USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Option [Member]
Compensation expense for benefit plans	$ 18.7	$ 17.8	$ 18.5
Income tax benefit from compensation expense for benefit plans	6.9	6.8	7.1
Total intrinsic value of options exercised	147.2	95.8	113.6
Cash received from the exercise of stock options	$ 59.6	$ 59.7	$ 54.9
Weighted-average grant date fair value of options awarded	$ 38.18	$ 29.98	$ 23.57
Weighted-average remaining contractual life of options currently exercisable, years	4 years 6 months 21 days	4 years 9 months 9 days	5 years 1 month 16 days