Goodwill and Purchased Intangible Assets - Purchased Intangible Assets, Net (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Purchased Intangible Assets [Line Items]
Gross	$ 1,049,700,000		$ 962,300,000
Accumulated Amortization	(705,700,000)		(686,700,000)
Accumulated Impairments and Other Charges	(57,900,000)		(57,900,000)
Net	286,100,000		217,700,000
Total purchased intangible assets	1,098,700,000		1,011,300,000
Net	335,100,000		266,700,000
Amortization of intangible assets	19,000,000.0	$ 9,900,000
Impairment of intangible assets	0	$ 0
In-process research and development
Purchased Intangible Assets [Line Items]
Indefinite-lived intangible assets:	49,000,000.0		49,000,000.0
Technologies and patents
Purchased Intangible Assets [Line Items]
Gross	903,800,000		823,500,000
Accumulated Amortization	(613,200,000)		(598,200,000)
Accumulated Impairments and Other Charges	(55,100,000)		(55,100,000)
Net	235,500,000		170,200,000
Customer relationships
Purchased Intangible Assets [Line Items]
Gross	136,300,000		129,200,000
Accumulated Amortization	(87,800,000)		(84,400,000)
Accumulated Impairments and Other Charges	(2,800,000)		(2,800,000)
Net	45,700,000		42,000,000.0
Trade names and other
Purchased Intangible Assets [Line Items]
Gross	9,600,000		9,600,000
Accumulated Amortization	(4,700,000)		(4,100,000)
Accumulated Impairments and Other Charges	0		0
Net	$ 4,900,000		$ 5,500,000