Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenue	$ 5,517.9	$ 5,878.3	$ 5,543.1
Cost of revenue (exclusive of amortization shown below)	3,544.3	3,639.6	3,507.5
Gross profit	1,973.6	2,238.7	2,035.6
Operating expenses:
Research and development	640.9	650.7	594.7
Selling and marketing	301.0	324.7	316.6
General and administrative	284.0	293.3	285.0
Litigation settlement	169.5	0.0	0.0
Amortization of acquisition-related intangible assets	115.2	111.7	123.8
Restructuring, asset impairments and other charges, net	28.7	4.3	20.8
Goodwill and intangible asset impairment	1.6	6.8	13.1
Total operating expenses	1,540.9	1,391.5	1,354.0
Operating income	432.7	847.2	681.6
Other income (expense), net:
Interest expense	(148.3)	(128.2)	(141.2)
Interest income	10.2	6.1	3.0
Loss on debt refinancing and prepayment	(6.2)	(4.6)
Gain on divestiture of business	0.0	5.0	12.5
Licensing income	0.0	36.6	47.6
Other expense	(11.8)	(7.1)	(8.8)
Other income (expense), net	(156.1)	(92.2)	(134.1)
Income before income taxes	276.6	755.0	547.5
Income tax (provision) benefit	(62.7)	(125.1)	265.5
Net income	213.9	629.9	813.0
Less: Net income attributable to non-controlling interest	(2.2)	(2.5)	(2.3)
Net income attributable to ON Semiconductor Corporation	211.7	627.4	810.7
Comprehensive income (loss), net of tax:
Net income	213.9	629.9	813.0
Foreign currency translation adjustments	0.1	0.7	7.0
Effects of cash flow hedges	(16.5)
Effects of cash flow hedges		2.0	2.6
Other comprehensive income (loss), net of tax	(16.4)	2.7	9.6
Comprehensive income	197.5	632.6	822.6
Comprehensive income attributable to non-controlling interest	(2.2)	(2.5)	(2.3)
Comprehensive income attributable to ON Semiconductor Corporation	$ 195.3	$ 630.1	$ 820.3
Net income per common share attributable to ON Semiconductor Corporation:
Basic (in dollars per share)	$ 0.52	$ 1.48	$ 1.92
Diluted (in dollars per share)	$ 0.51	$ 1.44	$ 1.89
Weighted-average common shares outstanding:
Basic (in shares)	410.9	423.8	421.9
Diluted (in shares)	416.0	435.9	428.3