Other Comprehensive Income (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Reclassification adjustments, before tax:
Amortization of net actuarial loss relating to VEBAs, before tax	$ 0.4	[1]	$ 0.7	[1]	$ 0.7	[1]	$ 1.5	[1]
Amortization of prior service cost relating to VEBAs, before tax	1.0	[1]	1.1	[1]	2.1	[1]	2.1	[1]
Reclassification of unrealized gain upon sale of available for sale securities, before tax	(0.2)	[2]	0		(0.6)	[2]	0
Unrealized gain on available for sale securities, before tax	0.2		0		0.5		0.3
Foreign currency translation adjustment, before tax	0.4		0.4		0.8		0.1
Other comprehensive income, before tax	1.8		2.2		3.5		4.0
Reclassification adjustments, income tax (expense) benefit:
Amortization of net actuarial loss relating to VEBAs, Income tax (expense) benefit	(0.1)	[3]	(0.3)	[3]	(0.2)	[3]	(0.6)	[3]
Amortization of prior service cost relating to VEBAs, Income tax (expense) benefit	(0.4)	[3]	(0.4)	[3]	(0.8)	[3]	(0.8)	[3]
Reclassification of unrealized gain upon sale of available for sale securities, income tax (expense) benefit	0.1	[3]			0.2	[3]
Unrealized gain on available for sale securities, Income tax (expense) benefit	(0.1)		0		(0.2)		0
Foreign currency translation adjustment, Income tax (expense) benefit	0		0		0		0
Other comprehensive income, Income tax (expense) benefit	(0.5)		(0.7)		(1.0)		(1.4)
Reclassification adjustments, net of tax:
Amortization of net actuarial loss relating to VEBAs, net of tax	0.3		0.4		0.5		0.9
Amortization of prior service cost relating to VEBAs, net of tax	0.6		0.7		1.3		1.3
Reclassification of unrealized gain upon sale of available for sale securities, net of tax	(0.1)				(0.4)
Unrealized gain on available for sale securities, net of tax	0.1		0		0.3		0.3
Foreign currency translation adjustment, net of tax	0.4		0.4		0.8		0.1
Other comprehensive income, net of tax	$ 1.3		$ 1.5		$ 2.5		$ 2.6

[1] Amounts reclassified out of Accumulated other comprehensive income relating to VEBA adjustments were included as a component of Selling, administrative, research and development and general expense.

[2] Amounts reclassified out of Accumulated other comprehensive income relating to sales of available for sale securities were included as a component of Other (expense) income, net.

[3] Income tax amounts reclassified out of Accumulated other comprehensive income relating to VEBA adjustments and sales of available for sale securities were included as a component of Income tax provision.