Note 20 - Reportable Segments - Reportable Segments (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Depreciation (1)		$ 1,352		$ 1,399		$ 1,390
Research, development and engineering expenses (2)		995		1,154		1,031
Income tax (provision) benefit (3)		491		111		256
Net income attributable to Corning Incorporated		1,906		512		960
Operating Segments [Member]
Net sales of reportable segments and All Other	[2]	14,120	[1]	11,452	[1]	11,656
Depreciation (1)	[3]	1,315		1,215		1,192
Research, development and engineering expenses (2)	[4]	838		754		867
Income tax (provision) benefit (3)	[5]	(612)		(435)		(451)
Net income attributable to Corning Incorporated	[6]	2,296		1,628		1,701
Investment in affiliated companies, at equity		264		258		291
Segment assets (5)	[7]	18,954		19,022		18,026
Capital expenditures		1,699		928		1,899
Display Products [Member] | Operating Segments [Member]
Net sales of reportable segments and All Other		3,700		3,172		3,254
Depreciation (1)	[3]	605		548		583
Research, development and engineering expenses (2)	[4]	110		99		119
Income tax (provision) benefit (3)	[5]	(249)		(190)		(206)
Net income attributable to Corning Incorporated	[6]	960		717		786
Investment in affiliated companies, at equity		109		107		145
Segment assets (5)	[7]	8,498		8,777		9,022
Capital expenditures		710		311		872
Optical Communications [Member] | Operating Segments [Member]
Net sales of reportable segments and All Other		4,349		3,563		4,064
Depreciation (1)	[3]	224		242		237
Research, development and engineering expenses (2)	[4]	216		204		218
Income tax (provision) benefit (3)	[5]	(152)		(101)		(134)
Net income attributable to Corning Incorporated	[6]	553		366		489
Investment in affiliated companies, at equity		3		3		3
Segment assets (5)	[7]	3,183		2,868		3,004
Capital expenditures		301		127		329
Specialty Materials [Member] | Operating Segments [Member]
Net sales of reportable segments and All Other		2,008		1,884		1,594
Depreciation (1)	[3]	161		162		145
Research, development and engineering expenses (2)	[4]	208		155		154
Income tax (provision) benefit (3)	[5]	(99)		(113)		(81)
Net income attributable to Corning Incorporated	[6]	371		423		302
Investment in affiliated companies, at equity		6		4		3
Segment assets (5)	[7]	2,308		2,551		2,433
Capital expenditures		183		125		176
Environmental Technologies [Member] | Operating Segments [Member]
Net sales of reportable segments and All Other		1,586		1,370		1,499
Depreciation (1)	[3]	139		132		128
Research, development and engineering expenses (2)	[4]	111		100		118
Income tax (provision) benefit (3)	[5]	(72)		(52)		(70)
Net income attributable to Corning Incorporated	[6]	269		197		263
Investment in affiliated companies, at equity
Segment assets (5)	[7]	2,150		1,986		1,912
Capital expenditures		228		159		287
Life Science Products [Member] | Operating Segments [Member]
Net sales of reportable segments and All Other		1,234		998		1,015
Depreciation (1)	[3]	52		50		49
Research, development and engineering expenses (2)	[4]	33		26		21
Income tax (provision) benefit (3)	[5]	(51)		(37)		(40)
Net income attributable to Corning Incorporated	[6]	194		139		150
Investment in affiliated companies, at equity		4		2		3
Segment assets (5)	[7]	791		683		627
Capital expenditures		128		83		80
Other Segments [Member] | Operating Segments [Member]
Net sales of reportable segments and All Other		1,243		465		230
Depreciation (1)	[3]	134		81		50
Research, development and engineering expenses (2)	[4]	160		170		237
Income tax (provision) benefit (3)	[5]	11		58		80
Net income attributable to Corning Incorporated	[6]	(51)		(214)		(289)
Investment in affiliated companies, at equity		142		142		137
Segment assets (5)	[7]	2,024		2,157		1,028
Capital expenditures		$ 149		$ 123		$ 155

[1] Includes HSG’s net sales and long-lived assets as of December 31, 2021 and 2020. Refer to Note 3 (Investments) and Note 4 (HSG Transactions and Acquisitions) to the consolidated financial statements for more information.

[2] Net sales are attributed to countries based on location of customer.

[3] Depreciation expense for Corning’s reportable segments includes an allocation of depreciation of corporate property not specifically identifiable to a segment.

[4] Research, development and engineering expenses include direct project spending that is identifiable to a segment.

[5] Incometax (provision) benefit reflects a tax rate of 21%.

[6] Many of Corning’s administrative and staff functions are performed on a centralized basis. Where practicable, Corning charges these expenses to segments based upon the extent to which each business uses a centralized function. Other staff functions, such as corporate finance, human resources and legal, are allocated to segments, primarily as a percentage of sales. Expenses that are not allocated to the segments are included in the reconciliation of reportable segment net income (loss) to consolidated net income.

[7] Segment assets include inventory, accounts receivable, property, plant and equipment, net of accumulated depreciation, and associated equity companies. HSGa ssets are included as of December 31, 2020.