Condensed Statements of Shareholders' Equity (USD $) In Millions	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings (Accumulated Deficit) [Member]	Total
Balance at Dec. 31, 2009	$ 78.7	$ 823.1	$ (248.2)	$ 168.7	$ 822.3
Balance (in shares) at Dec. 31, 2009	78.7
Comprehensive income:
Net income	0	0	0	62.8	62.8
Translation adjustment	0	0	(0.6)	0	(0.6)
Net unrealized loss	0	0	(4.9)	0	(4.9)
Amortization of prior service costs and actuarial losses, net	0	0	7.4	0	7.4
Comprehensive income					64.7
Dividends paid:
Common stock ($0.60 per share)	0	0	0	(47.5)	(47.5)
Common stock issued for:
Stock options exercised	0.2	2.3	0	0	2.5
Stock options exercised (in shares)	0.2				0.2
Employee benefit plans	0.6	9.6	0	0	10.2
Employee benefit plans (in shares)	0.6
Other transactions	0.1	2.2	0	0	2.3
Other transactions (in shares)	0.1
Stock-based compensation	0	2.9	0	0	2.9
Balance at Sep. 30, 2010	79.6	840.1	(246.3)	184.0	857.4
Balance (in shares) at Sep. 30, 2010	79.6
Balance at Dec. 31, 2010	79.6	842.3	(261.8)	170.2	830.3
Balance (in shares) at Dec. 31, 2010	79.6
Comprehensive income:
Net income	0	0	0	223.0	223.0
Translation adjustment	0	0	2.3	0	2.3
Net unrealized loss	0	0	(20.2)	0	(20.2)
Amortization of prior service costs and actuarial losses, net	0	0	9.1	0	9.1
Comprehensive income					214.2
Dividends paid:
Common stock ($0.60 per share)	0	0	0	(48.0)	(48.0)
Common stock repurchased and retired	(0.1)	(2.1)	0	0	(2.2)
Common stock repurchased and retired (in shares)	(0.1)				(0.1)
Common stock issued for:
Stock options exercised	0.5	8.8	0	0	9.3
Stock options exercised (in shares)	0.5				0.5
Other transactions	0.2	3.6	0	0	3.8
Other transactions (in shares)	0.2
Stock-based compensation	0	(0.2)	0	0	(0.2)
Balance at Sep. 30, 2011	$ 80.2	$ 852.4	$ (270.6)	$ 345.2	$ 1,007.2
Balance (in shares) at Sep. 30, 2011	80.2