Goodwill and Intangible Assets - Changes in Goodwill (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2021	Dec. 31, 2020
Goodwill [Roll Forward]
Goodwill		$ 1,766.9
Accumulated impairment loss		(170.9)
Goodwill, Beginning balance	$ 1,596.0
Impact of changes in foreign currency	(20.7)
Net goodwill, ending balance	1,575.3
Power Transmission Technologies [Member]
Goodwill [Roll Forward]
Goodwill		452.4
Accumulated impairment loss		(31.8)
Goodwill, Beginning balance	420.6
Impact of changes in foreign currency	(5.6)
Net goodwill, ending balance	415.0
Automation & Specialty [Member]
Goodwill [Roll Forward]
Goodwill		1,314.5
Accumulated impairment loss		$ (139.1)
Goodwill, Beginning balance	1,175.4
Impact of changes in foreign currency	(15.1)
Net goodwill, ending balance	$ 1,160.3

Goodwill foreign currency divestiture and other adjustments.

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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(10)(1))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

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-Publisher FASB
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- Definition

Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267

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- Definition

Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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-Paragraph 1
-Subparagraph (h)
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

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