Goodwill and Other Intangible Assets (Details 1) - USD ($) $ in Millions	9 Months Ended
	Jun. 30, 2016	Sep. 30, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Total, carrying amount	$ 439.1	$ 440.5
Total, net	213.4	229.5
Finite-lived intangible assets acquired	8.3
Other intangible assets
Amortized intangible assets, carrying amount	395.4	396.8
Amortized intangible assets, accumulated amortization	225.7	211.0
Amortized intangible assets, net	169.7	185.8
Goodwill and Other Intangible Assets (Textual) [Abstract]
Estimated amortization expense in 2016	28.8
Estimated amortization expense in 2017	26.1
Estimated amortization expense in 2018	20.4
Estimated amortization expense in 2019	17.7
Estimated amortization expense in 2020	15.1
Trademarks [Member]
Indefinite-lived Intangible Assets [Line Items]
Allen-Bradley® trademark not subject to amortization	43.7	43.7
Computer software products [Member]
Other intangible assets
Amortized intangible assets, carrying amount	182.4	182.4
Amortized intangible assets, accumulated amortization	100.8	91.9
Amortized intangible assets, net	81.6	90.5
Customer relationships [Member]
Other intangible assets
Amortized intangible assets, carrying amount	85.5	87.2
Amortized intangible assets, accumulated amortization	51.6	50.1
Amortized intangible assets, net	33.9	37.1
Technology [Member]
Other intangible assets
Amortized intangible assets, carrying amount	86.0	83.4
Amortized intangible assets, accumulated amortization	47.5	44.1
Amortized intangible assets, net	38.5	39.3
Trademarks [Member]
Other intangible assets
Amortized intangible assets, carrying amount	30.5	32.3
Amortized intangible assets, accumulated amortization	17.0	16.3
Amortized intangible assets, net	13.5	16.0
Other [Member]
Other intangible assets
Amortized intangible assets, carrying amount	11.0	11.5
Amortized intangible assets, accumulated amortization	8.8	8.6
Amortized intangible assets, net	$ 2.2	$ 2.9