Share-Based Compensation Plans Share-Based Compensation Plans - Stock Option Activity (Details) (Stock Options, USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares outstanding, beginning of period	193,000	201,000	354,000
Shares granted	0	0	0
Shares exercised	(182,000)	(7,000)	(153,000)
Shares cancelled/forfeited	(1,000)	(1,000)	0
Shares outstanding, end of period	10,000	193,000	201,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Shares outstanding, weighted average exercise price, beginning of period	$ 36.04	$ 36.30	$ 36.52
Shares granted, weighted average exercise price	$ 0	$ 0.00	$ 0.00
Shares exercised, weighted average exercise price	$ 35.26	$ 42.94	$ 36.80
Shares cancelled/forfeited, weighted average exercise price	$ 49.95	$ 36.12	$ 0.00
Shares outstanding, weighted average exercise price, end of period	$ 48.63	$ 36.04	$ 36.30