Investments (Results From Operations) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Net sales	$ 2,561		$ 2,940		$ 4,952	$ 5,752
Gross margin	756		1,065		1,317	2,164
Net income	(65)	$ (96)	105	$ 505
Corning’s equity in earnings of affiliated companies	79		33		93	58
Current assets	6,846				6,846		$ 7,463
Noncontrolling interests	84				84		$ 90
Gain on settlements of long-term sales agreements, net	62
Affiliated Companies [Member]
Net sales	160		181		345	366
Gross margin	7		64		66	144
Net income	163		76		203	139
Corning’s equity in earnings of affiliated companies	82		35		99	60
HSG [Member]
Net income	163		71		198	123
Pre-tax gain on settlements of long-term sales agreements	165
Inventory write-down	44
HSG [Member] | Intersegment Eliminations [Member]
Intercompany sales within HSG	$ 20		$ 33		$ 43	$ 54