Discontinued Operations - Results of Operations (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
	Jan. 21, 2020	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Operating expenses:
Income (loss) from discontinued operations, net of taxes				$ 205.4	$ 12.6
Income (loss) from discontinued operations, net of taxes		$ (3.2)	$ 7.3	205.4	12.6
Discontinued Operations, Disposed of by Sale | Fairbanks Morse
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations
Net sales		0.0	70.5	7.6	128.4
Cost of sales		0.0	53.9	7.6	98.2
Gross profit		0.0	16.6	0.0	30.2
Operating expenses:
Selling, general, and administrative expenses		0.0	7.0	1.5	13.3
Other		0.0	0.0	(0.1)	0.0
Total operating expenses		0.0	7.0	1.4	13.3
Income (loss) from discontinued operations before income tax		0.0	9.6	(1.4)	16.9
Income tax benefit (expense)		0.0	(2.3)	0.3	(4.3)
Income (loss) from discontinued operations, net of taxes		0.0	7.3	(1.1)	12.6
Gain (loss) from sale of discontinued operations, net of taxes	$ 206.5	(3.2)	0.0	206.5	0.0
Income (loss) from discontinued operations, net of taxes		$ (3.2)	$ 7.3	$ 205.4	$ 12.6