Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Apr. 03, 2020	Mar. 29, 2019
Income Statement [Abstract]
Revenue	$ 1,277.9	$ 1,386.6
Cost of revenue (exclusive of amortization shown below)	875.2	872.9
Gross profit	402.7	513.7
Operating expenses:
Research and development	171.0	151.8
Selling and marketing	76.8	77.1
General and administrative	71.2	72.9
Amortization of acquisition-related intangible assets	32.3	25.7
Restructuring, asset impairments and other charges, net	32.8	5.6
Intangible asset impairment	0.0	1.2
Total operating expenses	384.1	334.3
Operating income	18.6	179.4
Other income (expense), net:
Interest expense	(42.5)	(31.7)
Interest income	1.9	2.5
Other income	0.1	2.1
Other income (expense), net	(40.5)	(27.1)
Income (loss) before income taxes	(21.9)	152.3
Income tax (provision) benefit	8.2	(38.2)
Net income (loss)	(13.7)	114.1
Less: Net income attributable to non-controlling interest	(0.3)	0.0
Net income (loss) attributable to ON Semiconductor Corporation	(14.0)	114.1
Comprehensive income (loss), net of tax:
Net income (loss)	(13.7)	114.1
Foreign currency translation adjustments	0.6	0.1
Effects of cash flow hedges	(12.8)	(5.9)
Other comprehensive loss, net of tax	(12.2)	(5.8)
Comprehensive income (loss)	(25.9)	108.3
Comprehensive income attributable to non-controlling interest	(0.3)	0.0
Comprehensive income (loss) attributable to ON Semiconductor Corporation	$ (26.2)	$ 108.3
Net income (loss) per common share attributable to ON Semiconductor Corporation:
Basic (in dollars per share)	$ (0.03)	$ 0.28
Diluted (in dollars per share)	$ (0.03)	$ 0.27
Weighted-average common shares outstanding:
Basic (in shares)	410.6	410.6
Diluted (in shares)	410.6	417.7