Condensed Consolidated Statements of Operations - USD ($) $ in Millions		3 Months Ended		6 Months Ended	9 Months Ended
	Jul. 01, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020
Net sales	$ 0	$ 634	$ 693	$ 1,481	$ 1,855
Cost of sales (exclusive of depreciation and amortization shown below)	0	500	586	1,211	1,514
Selling, general and administrative expense	0	56	61	128	164
Depreciation and amortization	0	47	48	43	143
Asset impairments	0	0	0	0	16
Business realignment costs	0	19	12	14	57
Other operating expense, net	0	4	4	17	15
Operating income (loss)	0	8	(18)	68	(54)
Interest expense, net	0	(25)	(28)	(89)	76
Other non-operating (income) expense, net	0	(8)	4	(11)	(12)
Reorganization Items	(3,126)	0	0	(2,970)	0
(Loss) income from continuing operations before income tax and earnings from unconsolidated entities	3,126	(9)	(50)	2,960	(118)
Income tax expense (benefit)	191	17	(5)	201	8
(Loss) income from continuing operations before earnings from unconsolidated entities	2,935	26	45	2,759	126
Earnings from unconsolidated entities, net of taxes	0	0	1	1	2
(Loss) income from continuing operations before earnings from unconsolidated entities	2,935	(26)	(44)	2,760	(124)
(Loss) income from discontinued operations, net of taxes	119	(76)	1	135	(79)
Net (loss) income	3,054	(102)	(43)	2,894	(203)
Net income attributable to noncontrolling interest	0	0	0	(1)	0
Net (loss) income attributable to Hexion Inc.	3,054	(102)	(43)	2,895	(203)
Accumulated Deficit [Member]
Net (loss) income		$ (102)	$ (43)	$ (160)	$ (203)
Net (loss) income attributable to Hexion Inc.	$ 3,054