Share-Based Compensation (Expense Related to Non-vested Stock Awards) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Total pre-tax share-based compensation expense	$ 15.8		$ 12.9		$ 12.5
Excess tax benefit (deficiency) on share-based compensation	(0.5)	[1]	(0.7)	[1]	(0.6)	[1]
Non-Qualified Stock Option Expense [Member]
Total pre-tax share-based compensation expense	2.3		5.5		4.9
Non-Vested Stock Awards Expense [Member]
Total pre-tax share-based compensation expense	0		0.2		1.7
Immediately Vested Stock Awards Expense [Member]
Total pre-tax share-based compensation expense	0.8		0		0
Stock Unit Awards [Member]
Total pre-tax share-based compensation expense	8.0		5.2		4.5
Performance-Based Non-Vested Stock Awards Expense [Member]
Total pre-tax share-based compensation expense	$ 4.7		$ 2.0		$ 1.4

[1] Cash inflows (outflows) recognized as financing and operating activities in the Company’s consolidated statement of cash flows