Note 14 - Reportable Segments - Reportable Segments (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Depreciation (1)				$ 687	$ 666
Research, development, and engineering expenses		$ 240	$ 242	488	464
Income tax provision (3)		166	67	346	293
Net income attributable to Corning Incorporated		563	449	1,144	1,048
Operating Segments [Member]
Net sales of reportable segments		3,762	3,504	7,506	6,767
Depreciation (1)	[1]	341	332	681	659
Research, development, and engineering expenses	[2]	203	200	416	387
Income tax provision (3)	[3]	(170)	(158)	(330)	(294)
Net income attributable to Corning Incorporated	[4]	625	595	1,210	1,108
Optical Communications [Member] | Operating Segments [Member]
Net sales of reportable segments		1,313	1,075	2,511	2,012
Depreciation (1)	[1]	68	58	127	116
Research, development, and engineering expenses	[2]	58	52	113	103
Income tax provision (3)	[3]	(51)	(64)	(96)	(120)
Net income attributable to Corning Incorporated	[4]	182	148	348	259
Display Products [Member] | Operating Segments [Member]
Net sales of reportable segments		878	939	1,837	1,802
Depreciation (1)	[1]	146	149	302	297
Research, development, and engineering expenses	[2]	30	26	61	48
Income tax provision (3)	[3]	(59)	(40)	(122)	(71)
Net income attributable to Corning Incorporated	[4]	228	248	464	461
Specialty Materials [Member] | Operating Segments [Member]
Net sales of reportable segments		485	483	978	934
Depreciation (1)	[1]	42	42	82	83
Research, development, and engineering expenses	[2]	44	49	97	94
Income tax provision (3)	[3]	(24)	(22)	(44)	(46)
Net income attributable to Corning Incorporated	[4]	91	81	166	172
Environmental Technologies [Member] | Operating Segments [Member]
Net sales of reportable segments		356	407	765	848
Depreciation (1)	[1]	34	35	67	71
Research, development, and engineering expenses	[2]	24	29	49	56
Income tax provision (3)	[3]	(16)	(21)	(36)	(41)
Net income attributable to Corning Incorporated	[4]	62	81	136	155
Life Science Products [Member] | Operating Segments [Member]
Net sales of reportable segments		312	312	622	612
Depreciation (1)	[1]	16	14	30	26
Research, development, and engineering expenses	[2]	9	8	18	16
Income tax provision (3)	[3]	(10)	(14)	(21)	(27)
Net income attributable to Corning Incorporated	[4]	37	52	79	100
Hemlock and Emerging Growth Businesses [Member]
Net sales of reportable segments		418	288	793	559
Depreciation (1)	[1]	35	34	73	66
Research, development, and engineering expenses	[2]	38	36	78	70
Income tax provision (3)	[3]	(10)	3	(11)	11
Net income attributable to Corning Incorporated	[4]	$ 25	$ (15)	$ 17	$ (39)

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

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

[3] Income tax (provision) benefit reflects a tax rate of 21%.

[4] 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.