Revenue from Contracts with Customers - Contract Assets and Liabilities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Contract Assets, Current [Roll Forward]
Balance as of beginning of fiscal year	$ 51.2
Recognized in current year	23.9	$ 23.4
Reclassified to accounts receivable	(26.4)	(22.1)
Impairment	0.0	0.0
Reclassification to/from long-term	0.0	0.8
Balance as of period end	48.7	38.6
Contract Assets, Noncurrent [Roll Forward]
Balance as of beginning of fiscal year	0.1
Recognized in current year	0.0	0.0
Reclassified to accounts receivable	0.0	0.0
Impairment	0.0	0.0
Reclassification to/from short-term	0.0	(0.8)
Balance as of period end	0.1	16.1
Contract Liabilities, Current [Roll Forward]
Balance as of beginning of fiscal year	71.4
Recognized in current year	38.6	8.4
Amounts in beginning balance reclassified to revenue	(29.3)	(14.1)
Current year amounts reclassified to revenue	(2.8)	(0.3)
Other	0.0	0.0
Reclassification to/from long-term	0.0	2.5
Balance as of period end	77.9	66.2
Contract Liabilities, Noncurrent [Roll Forward]
Balance as of beginning of fiscal year	7.3
Recognized in current year	0.3	0.2
Amounts in beginning balance reclassified to revenue	(0.3)	(0.2)
Current year amounts reclassified to revenue	0.0	0.0
Other	0.0	0.0
Reclassification to/from short-term	0.0	(2.5)
Balance as of period end	$ 7.3	$ 19.7