Goodwill and Purchased Intangible Assets - Purchased Intangible Assets, Net (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross	$ 1,059.0	$ 1,059.0
Accumulated Amortization	(909.3)	(840.6)
Accumulated Impairments and Other Charges	(57.9)	(57.9)
Net	91.8	160.5
Technologies and patents
Finite-Lived Intangible Assets [Line Items]
Gross	913.1	913.1
Accumulated Amortization	(779.1)	(721.3)
Accumulated Impairments and Other Charges	(55.1)	(55.1)
Net	78.9	136.7
Customer contracts, support agreements, and related relationships
Finite-Lived Intangible Assets [Line Items]
Gross	136.3	136.3
Accumulated Amortization	(120.9)	(111.2)
Accumulated Impairments and Other Charges	(2.8)	(2.8)
Net	12.6	22.3
Trade names and other
Finite-Lived Intangible Assets [Line Items]
Gross	9.6	9.6
Accumulated Amortization	(9.3)	(8.1)
Accumulated Impairments and Other Charges	0.0	0.0
Net	$ 0.3	$ 1.5