Stock-Based Compensation (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended			3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 Performance Based Restricted Stock Units (RSU) [Member]	Sep. 30, 2011 PSU Other Than TSR [Member]	Jun. 30, 2012 PSU Other Than TSR [Member]
Pre-tax stock-based compensation	$ 9.1	$ 8.6	$ 18.5	$ 16.8
Performance-based stock units awarded					1.0	0.7
Non-TSR PSU Vesting Period Minimum						2
Non-TSR PSU Vesting Period Maximum						7
Vesting period, years					3
Percentage of units that are earned, minimum					0.00%
Percentage of units that are earned, maximum					200.00%
Performance-based stock, outstanding					2.1		0.7
Shares entitled to recipients					1.6
Percentage of units granted assumed					100.00%