Goodwill and Other Intangible Assets (Details 1) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired during year	$ 57.5	$ 5.4
Other intangible assets
Amortized intangible assets, carrying amount	441.3	396.8
Amortized intangible assets, accumulated amortization	229.7	211.0
Amortized intangible assets, net	211.6	185.8
Intangible asset amortization expense	28.9	29.4	$ 30.0
Allen-Bradley® trademark not subject to amortization	43.7	43.7
Total other intangible assets, carrying amount	485.0	440.5
Total other intangible assets, net	255.3	229.5
Goodwill and Other Intangible Assets (Textuals) [Abstract]
Estimated amortization expense in 2017	30.1
Estimated amortization expense in 2018	25.1
Estimated amortization expense in 2019	22.0
Estimated amortization expense in 2020	19.0
Estimated amortization expense in 2021	18.4
Computer software products [Member]
Other intangible assets
Amortized intangible assets, carrying amount	182.4	182.4
Amortized intangible assets, accumulated amortization	103.4	91.9
Amortized intangible assets, net	79.0	90.5
Intangible asset amortization expense	11.5	9.4	$ 9.4
Customer relationships [Member]
Other intangible assets
Amortized intangible assets, carrying amount	112.6	87.2
Amortized intangible assets, accumulated amortization	51.9	50.1
Amortized intangible assets, net	60.7	37.1
Technology [Member]
Other intangible assets
Amortized intangible assets, carrying amount	103.9	83.4
Amortized intangible assets, accumulated amortization	48.5	44.1
Amortized intangible assets, net	55.4	39.3
Trademarks [Member]
Other intangible assets
Amortized intangible assets, carrying amount	31.4	32.3
Amortized intangible assets, accumulated amortization	17.0	16.3
Amortized intangible assets, net	14.4	16.0
Other [Member]
Other intangible assets
Amortized intangible assets, carrying amount	11.0	11.5
Amortized intangible assets, accumulated amortization	8.9	8.6
Amortized intangible assets, net	$ 2.1	$ 2.9