Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2021	Oct. 02, 2020	Oct. 01, 2021	Oct. 02, 2020
Income Statement [Abstract]
Revenue	$ 1,742.1	$ 1,317.3	$ 4,893.7	$ 3,808.7
Cost of revenue (exclusive of amortization shown below)	1,021.3	876.1	3,011.6	2,590.5
Gross profit	720.8	441.2	1,882.1	1,218.2
Operating expenses:
Research and development	154.5	156.1	494.4	483.2
Selling and marketing	68.4	65.3	223.4	207.7
General and administrative	75.7	62.2	221.3	196.3
Amortization of acquisition-related intangible assets	24.7	29.6	74.5	91.0
Restructuring, asset impairments and other charges, net	(1.7)	9.0	58.3	58.0
Intangible asset impairment	0.0	0.0	2.9	1.3
Total operating expenses	321.6	322.2	1,074.8	1,037.5
Operating income	399.2	119.0	807.3	180.7
Other income (expense), net:
Interest expense	(31.9)	(42.2)	(98.4)	(126.6)
Interest income	0.5	0.9	1.1	4.3
Loss on debt refinancing and prepayment	0.0	0.0	(26.2)	0.0
Gain on divestiture of business	10.2	0.0	10.2	0.0
Other income (expense)	(5.8)	0.4	(2.4)	(2.3)
Other income (expense), net	(27.0)	(40.9)	(115.7)	(124.6)
Income before income taxes	372.2	78.1	691.6	56.1
Income tax (provision) benefit	(61.8)	83.1	(106.8)	90.5
Net income	310.4	161.2	584.8	146.6
Less: Net income attributable to non-controlling interest	(0.7)	(0.6)	(1.1)	(1.4)
Net income attributable to ON Semiconductor Corporation	309.7	160.6	583.7	145.2
Comprehensive income, net of tax:
Net income	310.4	161.2	584.8	146.6
Foreign currency translation adjustments	(0.3)	0.6	(2.8)	1.1
Effects of cash flow hedges	3.9	3.6	11.8	(10.2)
Other comprehensive income (loss), net of tax	3.6	4.2	9.0	(9.1)
Comprehensive income	314.0	165.4	593.8	137.5
Comprehensive income attributable to non-controlling interest	(0.7)	(0.6)	(1.1)	(1.4)
Comprehensive income attributable to ON Semiconductor Corporation	$ 313.3	$ 164.8	$ 592.7	$ 136.1
Net income per share of common stock attributable to ON Semiconductor Corporation:
Basic (in dollars per share)	$ 0.72	$ 0.39	$ 1.38	$ 0.35
Diluted (in dollars per share)	$ 0.70	$ 0.38	$ 1.32	$ 0.35
Weighted-average shares of common stock outstanding:
Basic (in shares)	430.6	410.8	423.8	410.5
Diluted (in shares)	440.7	418.3	443.1	414.4