Retirement Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Contributions to pension plans	$ 7.5		$ 17.0
Contributions to retiree health care plan	0.5		1.5
Total expected employer contributions in current fiscal year	21.0		21.0
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2.5	2.6	7.7	7.9
Interest cost	3.7	3.9	11.2	11.7
Expected return on assets	(3.6)	(3.8)	(10.9)	(11.5)
Other	0.5	0.2	1.3	0.4
Total benefit cost	3.1	2.9	9.3	8.5
Retiree Health Care Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	0	0	0	0.1
Interest cost	0.3	0.4	1.0	1.0
Total benefit cost	$ 0.3	$ 0.4	$ 1.0	$ 1.1