Condensed Statements of Shareholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Loss	Retained Earnings
Balance (in shares) at Dec. 31, 2017		167.1
Balance at Dec. 31, 2017	$ 2,753.7	$ 167.1	$ 2,280.9	$ (484.6)	$ 790.3
Income tax reclassification adjustment	0.0	0.0	0.0	(85.9)	85.9
Net income	20.9	0.0	0.0	0.0	20.9
Other comprehensive income (loss)	17.7	0.0	0.0	17.7	0.0
Dividends paid:
Common stock ($0.20 per share)	$ (33.4)	$ 0.0	0.0	0.0	(33.4)
Common stock issued for:
Stock options exercised (in shares)	0.1	0.1
Stock options exercised	$ 1.0	$ 0.1	0.9	0.0	0.0
Other Transactions (in shares)		0.0
Other Transactions	0.5	$ 0.0	0.5	0.0	0.0
Stock-based compensation	2.7	$ 0.0	2.7	0.0	0.0
Balance (in shares) at Mar. 31, 2018		167.2
Balance at Mar. 31, 2018	2,763.1	$ 167.2	2,285.0	(552.8)	863.7
Balance (in shares) at Dec. 31, 2018		165.3
Balance at Dec. 31, 2018	2,832.2	$ 165.3	2,247.4	(651.0)	1,070.5
Lease accounting adoption adjustment	11.2	0.0	0.0	0.0	11.2
Net income	41.7	0.0	0.0	0.0	41.7
Other comprehensive income (loss)	(5.9)	0.0	0.0	(5.9)	0.0
Dividends paid:
Common stock ($0.20 per share)	(33.0)	$ 0.0	0.0	0.0	(33.0)
Common stock repurchased and retired (in shares)		(0.6)
Common stock repurchased and retired	$ (13.2)	$ (0.6)	(12.6)	0.0	0.0
Common stock issued for:
Stock options exercised (in shares)	0.1	0.1
Stock options exercised	$ 1.4	$ 0.1	1.3	0.0	0.0
Other Transactions (in shares)		0.1
Other Transactions	0.4	$ 0.1	0.3	0.0	0.0
Stock-based compensation	2.8	$ 0.0	2.8	0.0	0.0
Balance (in shares) at Mar. 31, 2019		164.9
Balance at Mar. 31, 2019	$ 2,837.6	$ 164.9	$ 2,239.2	$ (656.9)	$ 1,090.4