Restructuring Charges (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended		3 Months Ended	6 Months Ended
	Dec. 31, 2012 employee	Jun. 30, 2013	Jun. 30, 2013 Employee Severance [Member] employee	Jun. 30, 2013 Employee Severance [Member] employee
Restructuring Cost and Reserve [Line Items]
Non-retirement postemployment benefit charges	$ 4.6
Non-retirement postemployment benefits, employees	178
Restructuring charges			0.4	2.9
Restructuring charges, employees affected			12	59
Payments made for restructuring charges			2.5	4.5
Restructuring reserve, remaining accrual		$ 2.9