Acquisition - Schedule of Purchase Consideration and Net Asset Allocation (Details) - USD ($) $ in Millions		9 Months Ended
	Jul. 01, 2015	Sep. 30, 2015	Dec. 31, 2014
Consideration Transferred [Abstract]
Cash consideration to be paid to Audience shareholders and equity award holders		$ 61.6
Net Assets Acquired [Abstract]
Goodwill		$ 934.1	$ 914.7
Audience, Inc.
Consideration Transferred [Abstract]
Cash consideration to be paid to Audience shareholders and equity award holders	$ 61.6
Fair value of shares of Knowles common stock issued to Audience shareholders and equity award holders	60.2
Fair value of restricted stock units assumed	1.5
Fair value of total consideration	123.3
Net Assets Acquired [Abstract]
Goodwill	47.7
Cash	26.5
Identified intangible assets	25.9
Inventories	10.4
Property, plant, and equipment	10.7
Other assets	19.5
Total liabilities and accruals	(17.4)
Net Assets Acquired	$ 123.3