Investments (Results From Operations) (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Net sales	$ 3,001			$ 2,934			$ 7,953	$ 8,686
Gross profit	1,001			1,017			2,318	3,181
Net (loss) income	432	$ (65)	$ (96)	341	$ 105	$ 505
Corning’s equity in earnings of affiliated companies	(76)			23			17	81
Affiliated Companies [Member]
Net sales	78			200			423	566
Gross profit	21			61			87	205
Net (loss) income	(192)			46			11	185
Corning’s equity in earnings of affiliated companies	(77)			21			22	81
HSG [Member]
Net (loss) income	(154)			42			44	165
HSG [Member] | Intersegment Eliminations [Member]
Intercompany sales within HSG	$ 12			$ 31			$ 55	$ 85