Share-Based Compensation (Expense Related to Non-vested Stock Awards) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Total pre-tax share-based compensation expense	$ 12.5		$ 11.7		$ 9.3
Excess tax benefit on share-based compensation	(0.6)	[1]	1.0	[1]	(0.1)	[1]
Non-Qualified Stock Option Expense [Member]
Total pre-tax share-based compensation expense	4.9		4.8		4.2
Non-Vested Stock Awards Expense [Member]
Total pre-tax share-based compensation expense	1.7		2.8		4.2
Stock Unit Awards [Member]
Total pre-tax share-based compensation expense	4.5		3.1		0.9
Performance-Based Non-Vested Stock Awards Expense [Member]
Total pre-tax share-based compensation expense	$ 1.4		$ 1.0		$ 0

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