Stock-Based Compensation Plans (Schedule of Share-based Payment Award, by Share-based Payment Award) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total grant date fair value	$ 4.8
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Instruments	0.1	1.2
Weighted average grant date fair value per instrument, in dollars per instrument	$ 2.79	$ 2.04
Total grant date fair value	0.4	2.4
Non-Qualified Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Instruments	0.1	0.6
Weighted average grant date fair value per instrument, in dollars per instrument	$ 1.67	$ 1.23
Total grant date fair value	0.1	0.7
Employee Stock Purchase Plan Instruments [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Instruments	0.1	0.1
Weighted average grant date fair value per instrument, in dollars per instrument	$ 2.14	$ 1.95
Total grant date fair value	0.2	0.3
Phantom Plan Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Instruments		0.4
Weighted average grant date fair value per instrument, in dollars per instrument		$ 2.03
Total grant date fair value	$ 1.3	$ 0.7