Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jul. 03, 2020	Jun. 28, 2019	Jul. 03, 2020	Jun. 28, 2019
Income Statement [Abstract]
Revenue	$ 1,213.5	$ 1,347.7	$ 2,491.4	$ 2,734.3
Cost of revenue (exclusive of amortization shown below)	839.2	848.7	1,714.4	1,721.6
Gross profit	374.3	499.0	777.0	1,012.7
Operating expenses:
Research and development	156.1	147.0	327.1	298.8
Selling and marketing	65.6	73.6	142.4	150.7
General and administrative	62.9	74.1	134.1	147.0
Amortization of acquisition-related intangible assets	29.1	27.5	61.4	53.2
Restructuring, asset impairments and other charges, net	16.2	18.1	49.0	23.7
Intangible asset impairment	1.3	0.4	1.3	1.6
Total operating expenses	331.2	340.7	715.3	675.0
Operating income	43.1	158.3	61.7	337.7
Other income (expense), net:
Interest expense	(41.9)	(33.7)	(84.4)	(65.4)
Interest income	1.5	3.0	3.4	5.5
Loss on debt refinancing and prepayment	0.0	(0.4)	0.0	(0.4)
Other income (expense)	(2.8)	(1.0)	(2.7)	1.1
Other income (expense), net	(43.2)	(32.1)	(83.7)	(59.2)
Income (loss) before income taxes	(0.1)	126.2	(22.0)	278.5
Income tax (provision) benefit	(0.8)	(23.3)	7.4	(61.5)
Net income (loss)	(0.9)	102.9	(14.6)	217.0
Less: Net income attributable to non-controlling interest	(0.5)	(1.1)	(0.8)	(1.1)
Net income (loss) attributable to ON Semiconductor Corporation	(1.4)	101.8	(15.4)	215.9
Comprehensive income (loss), net of tax:
Net income (loss)	(0.9)	102.9	(14.6)	217.0
Foreign currency translation adjustments	(0.1)	0.5	0.5	0.6
Effects of cash flow hedges	(1.0)	(10.2)	(13.8)	(16.1)
Other comprehensive loss, net of tax	(1.1)	(9.7)	(13.3)	(15.5)
Comprehensive income (loss)	(2.0)	93.2	(27.9)	201.5
Comprehensive income attributable to non-controlling interest	(0.5)	(1.1)	(0.8)	(1.1)
Comprehensive income (loss) attributable to ON Semiconductor Corporation	$ (2.5)	$ 92.1	$ (28.7)	$ 200.4
Net income (loss) per share of common stock attributable to ON Semiconductor Corporation:
Basic (in dollars per share)	$ (0.00)	$ 0.25	$ (0.04)	$ 0.52
Diluted (in dollars per share)	$ (0.00)	$ 0.24	$ (0.04)	$ 0.52
Weighted-average shares of common stock outstanding:
Basic (in shares)	410.1	411.9	410.3	411.3
Diluted (in shares)	410.1	417.7	410.3	417.8