Revenue Recognition - Dual Reporting - Consolidated Statements of Operations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Sales
Sales	$ 1,657.2	$ 1,651.2	$ 3,299.5	$ 3,237.8
Cost of sales
Cost of sales	(949.0)	(947.3)	(1,852.6)	(1,833.7)
Income tax provision	(56.4)	(72.2)	(96.9)	(606.4)
Impact of Adoption | Accounting Standards Update 2014-09
Cost of sales
Income tax provision	2.0		1.3
Balances without adoption of ASC 606
Cost of sales
Income tax provision	(54.4)		(95.6)
Products and solutions
Sales
Sales	1,466.8	1,470.5	2,924.4	2,883.0
Cost of sales
Cost of sales	(823.6)	(836.1)	(1,606.0)	(1,616.6)
Products and solutions | Impact of Adoption | Accounting Standards Update 2014-09
Sales
Sales	(2.0)		2.6
Cost of sales
Cost of sales	(2.7)		(3.8)
Products and solutions | Balances without adoption of ASC 606
Sales
Sales	1,464.8		2,927.0
Cost of sales
Cost of sales	(826.3)		(1,609.8)
Services
Sales
Sales	190.4	180.7	375.1	354.8
Cost of sales
Cost of sales	(125.4)	$ (111.2)	(246.6)	$ (217.1)
Services | Impact of Adoption | Accounting Standards Update 2014-09
Sales
Sales	(7.2)		(16.4)
Cost of sales
Cost of sales	5.0		13.8
Services | Balances without adoption of ASC 606
Sales
Sales	183.2		358.7
Cost of sales
Cost of sales	$ (120.4)		$ (232.8)