Share-Based Payments Stock Options (Details) (Options and Sosars [Member], USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Options and Sosars [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at the beginning of the period (in shares)	2.2
Granted (in shares)	0.1
Exercised (in shares)	(0.6)
Forfeited (in shares)	0
Outstanding at the end of the period (in shares)	1.7	2.2
Exercisable (in shares)	1.4
Weighted-average exercise price of shares outstanding, beginning of the period (in dollars per share)	$ 45.33
Weighted-average exercise price of shares granted (in dollars per share)	$ 74.81
Weighted-average exercise price of shares exercised (in dollars per share)	$ 44.89
Weighted-average exercise price of shares forfeited (in dollars per share)	$ 0.00
Weighted-average exercise price of shares outstanding, end of the period (in dollars per share)	$ 47.87	$ 45.33
Weighted-average exercise price of shares exercisable (in dollars per share)	$ 45.06
Weighted-average remaining contractual life, outstanding (in years)	5 years	5 years
Weighted-average remaining contractual life, outstanding (in years)	5 years	5 years
Weighted-average remaining contractual life, exercisable (in years)	4 years 3 months 18 days
Aggregate intrinsic value of shares outstanding (in dollars)	$ 64.6
Aggregate intrinsic value of shares outstanding (in dollars)	44.7	64.6
Aggregate intrinsic value of shares exercisable (in dollars)	$ 42.2