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, 2016		165.4
Balance at Dec. 31, 2016	$ 2,273.0	$ 165.4	$ 2,243.8	$ (510.0)	$ 373.8
Net income	13.4	0.0	0.0	0.0	13.4
Other comprehensive income	7.9	0.0	0.0	7.9	0.0
Dividends paid:
Common stock ($0.20 per share)	$ (33.1)	$ 0.0	0.0	0.0	(33.1)
Common stock issued for:
Stock options exercised (in shares)	0.5	0.5
Stock options exercised	$ 8.8	$ 0.5	8.3	0.0	0.0
Other Transactions (in shares)		0.0
Other Transactions	0.6	$ 0.0	0.6	0.0	0.0
Stock-based compensation	1.0	$ 0.0	1.0	0.0	0.0
Balance (in shares) at Mar. 31, 2017		165.9
Balance at Mar. 31, 2017	2,271.6	$ 165.9	2,253.7	(502.1)	354.1
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	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