Guarantor Non-Guarantor Subsidiary Financial Information (Details) - Consolidating Statement of Operations - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Net sales	$ 892	$ 995	$ 1,778	$ 1,941
Cost of sales	757	829	1,507	1,618
Gross profit	135	166	271	323
Selling, general and administrative expense	61	77	152	159
Gain on disposition	0	0	0	(44)
Asset impairments	0	0	0	25
Business realignment costs	(11)	(5)	(15)	(14)
Other operating expense, net	8	11	16	20
Operating income	55	73	88	149
Interest expense, net (contractual interest expense of $83 and $163 for the three and six months ended June 30, 2019, respectively)	9	84	89	167
Intercompany interest (income) expense, net	0	0	0	0
Other non-operating (income) expense, net	(10)	8	(11)	7
Reorganization Items	156	0	156	0
(Loss) income before tax and earnings from unconsolidated entities	100	19	146	25
Income tax expense	8	3	15	11	$ 40
Loss before earnings from unconsolidated entities	(108)	(22)	(161)	(36)
Earnings from unconsolidated entities, net of taxes	1	1	2	2
Net loss	(107)	(21)	(159)	(34)
Net income attributable to noncontrolling interest	(1)	(1)	(1)	(1)
Net loss attributable to Hexion Inc.	(108)	(22)	(160)	(35)
Comprehensive (loss) income attributable to Hexion Inc.	(116)	(38)	(168)	(37)
Hexion Inc. [Member]
Net sales	413	460	817	891
Cost of sales	339	370	680	727
Gross profit	74	90	137	164
Selling, general and administrative expense	25	44	76	80
Gain on disposition				(24)
Asset impairments				25
Business realignment costs	(3)	(3)	(5)	(9)
Other operating expense, net	6	3	13	3
Operating income	40	40	43	71
Interest expense, net (contractual interest expense of $83 and $163 for the three and six months ended June 30, 2019, respectively)	2	80	78	159
Intercompany interest (income) expense, net	(19)	(21)	(39)	(41)
Other non-operating (income) expense, net	(10)	36	8	17
Reorganization Items	156		156
(Loss) income before tax and earnings from unconsolidated entities	89	55	160	64
Income tax expense	1	1	1	(6)
Loss before earnings from unconsolidated entities	(90)	(56)	(161)	(58)
Earnings from unconsolidated entities, net of taxes	(18)	34	1	23
Net loss	(108)	(22)	(160)	(35)
Net income attributable to noncontrolling interest	0	0	0	0
Net loss attributable to Hexion Inc.	(108)	(22)	(160)	(35)
Comprehensive (loss) income attributable to Hexion Inc.	(116)	(38)	(168)	(37)
Combined Subsidiary Guarantors [Member]
Net sales	0	0	0	0
Cost of sales	0	0	0	0
Gross profit	0	0	0	0
Selling, general and administrative expense	0	0	0	0
Gain on disposition				0
Asset impairments				0
Business realignment costs	0	0	0	0
Other operating expense, net	0	0	0	0
Operating income	0	0	0	0
Interest expense, net (contractual interest expense of $83 and $163 for the three and six months ended June 30, 2019, respectively)	0	0	0	0
Intercompany interest (income) expense, net	0	0	0	0
Other non-operating (income) expense, net	0	0	0	0
Reorganization Items	0		0
(Loss) income before tax and earnings from unconsolidated entities	0	0	0	0
Income tax expense	0	0	0	0
Loss before earnings from unconsolidated entities	0	0	0	0
Earnings from unconsolidated entities, net of taxes	(13)	17	(1)	14
Net loss	(13)	17	(1)	14
Net income attributable to noncontrolling interest	0	0	0	0
Net loss attributable to Hexion Inc.	(13)	17	(1)	14
Comprehensive (loss) income attributable to Hexion Inc.	(13)	16	(1)	14
Combined Non-Guarantor Subsidiaries [Member]
Net sales	526	583	1,057	1,153
Cost of sales	465	507	923	994
Gross profit	61	76	134	159
Selling, general and administrative expense	36	33	76	79
Gain on disposition				(20)
Asset impairments				0
Business realignment costs	(8)	(2)	(10)	(5)
Other operating expense, net	2	8	3	17
Operating income	15	33	45	78
Interest expense, net (contractual interest expense of $83 and $163 for the three and six months ended June 30, 2019, respectively)	7	4	11	8
Intercompany interest (income) expense, net	19	21	39	41
Other non-operating (income) expense, net	0	(28)	(19)	(10)
Reorganization Items	0		0
(Loss) income before tax and earnings from unconsolidated entities	11	(36)	(14)	(39)
Income tax expense	7	2	14	17
Loss before earnings from unconsolidated entities	(18)	34	0	22
Earnings from unconsolidated entities, net of taxes	1	1	2	2
Net loss	(17)	35	2	24
Net income attributable to noncontrolling interest	(1)	(1)	(1)	(1)
Net loss attributable to Hexion Inc.	(18)	34	1	23
Comprehensive (loss) income attributable to Hexion Inc.	(25)	35	(6)	37
Consolidation, Eliminations [Member]
Net sales	(47)	(48)	(96)	(103)
Cost of sales	(47)	(48)	(96)	(103)
Gross profit	0	0	0	0
Selling, general and administrative expense	0	0	0	0
Gain on disposition				0
Asset impairments				0
Business realignment costs	0	0	0	0
Other operating expense, net	0	0	0	0
Operating income	0	0	0	0
Interest expense, net (contractual interest expense of $83 and $163 for the three and six months ended June 30, 2019, respectively)	0	0	0	0
Intercompany interest (income) expense, net	0	0	0	0
Other non-operating (income) expense, net	0	0	0	0
Reorganization Items	0		0
(Loss) income before tax and earnings from unconsolidated entities	0	0	0	0
Income tax expense	0	0	0	0
Loss before earnings from unconsolidated entities	0	0	0	0
Earnings from unconsolidated entities, net of taxes	31	(51)	0	(37)
Net loss	31	(51)	0	(37)
Net income attributable to noncontrolling interest	0	0	0	0
Net loss attributable to Hexion Inc.	31	(51)	0	(37)
Comprehensive (loss) income attributable to Hexion Inc.	$ 38	$ (51)	$ 7	$ (51)