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, 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 (loss) income	41.7	0.0	0.0	0.0	41.7
Other comprehensive (loss) income	(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
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
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
Net (loss) income	65.9
Other comprehensive (loss) income	$ (21.7)
Common stock issued for:
Stock options exercised (in shares)	0.1
Stock options exercised	$ 1.5
Balance (in shares) at Sep. 30, 2019		159.7
Balance at Sep. 30, 2019	2,664.7	$ 159.7	2,128.6	(672.7)	1,049.1
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
Net (loss) income	(20.0)	0.0	0.0	0.0	(20.0)
Other comprehensive (loss) income	(3.5)	0.0	0.0	(3.5)	0.0
Dividends paid:
Common stock ($0.20 per share)	(32.7)	$ 0.0	0.0	0.0	(32.7)
Common stock repurchased and retired (in shares)		(0.6)
Common stock repurchased and retired	(13.5)	$ (0.6)	(12.9)	0.0	0.0
Common stock issued for:
Stock options exercised (in shares)		0.0
Stock options exercised	0.1	$ 0.0	0.1	0.0	0.0
Other transactions (in shares)		0.0
Other transactions	0.9	$ 0.0	0.9	0.0	0.0
Stock-based compensation	1.9	$ 0.0	1.9	0.0	0.0
Balance (in shares) at Jun. 30, 2019		164.3
Balance at Jun. 30, 2019	2,770.8	$ 164.3	2,229.2	(660.4)	1,037.7
Net (loss) income	44.2	0.0	0.0	0.0	44.2
Other comprehensive (loss) income	(12.3)	0.0	0.0	(12.3)	0.0
Dividends paid:
Common stock ($0.20 per share)	(32.8)	$ 0.0	0.0	0.0	(32.8)
Common stock repurchased and retired (in shares)		(4.8)
Common stock repurchased and retired	(108.9)	$ (4.8)	(104.1)	0.0	0.0
Common stock issued for:
Other transactions (in shares)		0.2
Other transactions	1.8	$ 0.2	1.6	0.0	0.0
Stock-based compensation	1.9	$ 0.0	1.9	0.0	0.0
Balance (in shares) at Sep. 30, 2019		159.7
Balance at Sep. 30, 2019	2,664.7	$ 159.7	2,128.6	(672.7)	1,049.1
Balance (in shares) at Dec. 31, 2019		157.7
Balance at Dec. 31, 2019	2,417.5	$ 157.7	2,122.1	(803.4)	941.1
Net (loss) income	(80.0)	0.0	0.0	0.0	(80.0)
Other comprehensive (loss) income	(17.7)	0.0	0.0	(17.7)	0.0
Dividends paid:
Common stock ($0.20 per share)	(31.5)	$ 0.0	0.0	0.0	(31.5)
Common stock issued for:
Stock options exercised (in shares)		0.0
Stock options exercised	0.5	$ 0.0	0.5	0.0	0.0
Other transactions (in shares)		0.1
Other transactions	2.9	$ 0.1	2.8	0.0	0.0
Stock-based compensation	(2.6)	$ 0.0	(2.6)	0.0	0.0
Balance (in shares) at Mar. 31, 2020		157.8
Balance at Mar. 31, 2020	2,289.1	$ 157.8	2,122.8	(821.1)	829.6
Balance (in shares) at Dec. 31, 2019		157.7
Balance at Dec. 31, 2019	2,417.5	$ 157.7	2,122.1	(803.4)	941.1
Net (loss) income	(936.9)
Other comprehensive (loss) income	$ 75.2
Common stock issued for:
Stock options exercised (in shares)	0.1
Stock options exercised	$ 0.5
Balance (in shares) at Sep. 30, 2020		157.9
Balance at Sep. 30, 2020	1,469.1	$ 157.9	2,129.9	(728.2)	(90.5)
Balance (in shares) at Mar. 31, 2020		157.8
Balance at Mar. 31, 2020	2,289.1	$ 157.8	2,122.8	(821.1)	829.6
Net (loss) income	(120.1)	0.0	0.0	0.0	(120.1)
Other comprehensive (loss) income	47.2	0.0	0.0	47.2	0.0
Dividends paid:
Common stock ($0.20 per share)	(31.6)	$ 0.0	0.0	0.0	(31.6)
Common stock issued for:
Other transactions (in shares)		0.1
Other transactions	0.4	$ 0.1	0.3	0.0	0.0
Stock-based compensation	3.9	$ 0.0	3.9	0.0	0.0
Balance (in shares) at Jun. 30, 2020		157.9
Balance at Jun. 30, 2020	2,188.9	$ 157.9	2,127.0	(773.9)	677.9
Net (loss) income	(736.8)	0.0	0.0	0.0	(736.8)
Other comprehensive (loss) income	45.7	0.0	0.0	45.7	0.0
Dividends paid:
Common stock ($0.20 per share)	(31.6)	0.0	0.0	0.0	(31.6)
Common stock issued for:
Stock-based compensation	2.9	$ 0.0	2.9	0.0	0.0
Balance (in shares) at Sep. 30, 2020		157.9
Balance at Sep. 30, 2020	$ 1,469.1	$ 157.9	$ 2,129.9	$ (728.2)	$ (90.5)