Guarantor Non-Guarantor Subsidiary Financial Information (Details) - Consolidating Statement of Operations - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net sales	$ 995	$ 912	$ 1,941	$ 1,782
Cost of sales	829	778	1,618	1,515
Gross profit	166	134	323	267
Selling, general and administrative expense	77	77	159	156
Gain on disposition	0	0	(44)	0
Asset impairments	0	0	25	0
Business realignment costs	(5)	(10)	(14)	(17)
Other operating expense, net	11	9	20	3
Operating income	73	38	149	91
Interest expense, net	84	82	167	165
Intercompany interest (income) expense, net	0	0	0	0
Loss on extinguishment of debt	0	0	0	3
Other non-operating expense (income), net	8	(7)	7	(5)
(Loss) income before tax and earnings from unconsolidated entities	(19)	(37)	(25)	(72)
Income tax expense (benefit)	3	(1)	11	7
Loss before earnings from unconsolidated entities	(22)	(36)	(36)	(79)
Earnings from unconsolidated entities, net of taxes	1	2	2	3
Net loss	(21)	(34)	(34)	(76)
Net income attributable to noncontrolling interest	(1)	0	(1)	0
Net (loss) income attributable to Hexion Inc.	(22)	(34)	(35)	(76)
Comprehensive (loss) income attributable to Hexion Inc.	(38)	(25)	(37)	(61)
Hexion Inc. [Member]
Net sales	460	417	891	795
Cost of sales	370	355	727	677
Gross profit	90	62	164	118
Selling, general and administrative expense	44	34	80	67
Gain on disposition			(24)
Asset impairments			25
Business realignment costs	(3)	(6)	(9)	(10)
Other operating expense, net	3	3	3	(3)
Operating income	40	19	71	44
Interest expense, net	80	78	159	158
Intercompany interest (income) expense, net	(21)	(18)	(41)	(35)
Loss on extinguishment of debt				3
Other non-operating expense (income), net	36	(50)	17	(58)
(Loss) income before tax and earnings from unconsolidated entities	(55)	9	(64)	(24)
Income tax expense (benefit)	1	2	(6)	(4)
Loss before earnings from unconsolidated entities	(56)	7	(58)	(20)
Earnings from unconsolidated entities, net of taxes	34	(41)	23	(56)
Net loss	(22)		(35)
Net income attributable to noncontrolling interest	0		0
Net (loss) income attributable to Hexion Inc.	(22)	(34)	(35)	(76)
Comprehensive (loss) income attributable to Hexion Inc.	(38)	(25)	(37)	(61)
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	0	0	0	0
Intercompany interest (income) expense, net	0	0	0	0
Loss on extinguishment of debt				0
Other non-operating expense (income), net	0	0	0	0
(Loss) income before tax and earnings from unconsolidated entities	0	0	0	0
Income tax expense (benefit)	0	0	0	0
Loss before earnings from unconsolidated entities	0	0	0	0
Earnings from unconsolidated entities, net of taxes	17	(32)	14	(34)
Net loss	17		14
Net income attributable to noncontrolling interest	0		0
Net (loss) income attributable to Hexion Inc.	17	(32)	14	(34)
Comprehensive (loss) income attributable to Hexion Inc.	16	(31)	14	(34)
Combined Non-Guarantor Subsidiaries [Member]
Net sales	583	550	1,153	1,093
Cost of sales	507	478	994	944
Gross profit	76	72	159	149
Selling, general and administrative expense	33	43	79	89
Gain on disposition			(20)
Asset impairments			0
Business realignment costs	(2)	(4)	(5)	(7)
Other operating expense, net	8	6	17	6
Operating income	33	19	78	47
Interest expense, net	4	4	8	7
Intercompany interest (income) expense, net	21	18	41	35
Loss on extinguishment of debt				0
Other non-operating expense (income), net	(28)	43	(10)	53
(Loss) income before tax and earnings from unconsolidated entities	36	(46)	39	(48)
Income tax expense (benefit)	2	(3)	17	11
Loss before earnings from unconsolidated entities	34	(43)	22	(59)
Earnings from unconsolidated entities, net of taxes	1	1	2	2
Net loss	35		24
Net income attributable to noncontrolling interest	(1)		(1)
Net (loss) income attributable to Hexion Inc.	34	(42)	23	(57)
Comprehensive (loss) income attributable to Hexion Inc.	35	(46)	37	(49)
Consolidation, Eliminations [Member]
Net sales	(48)	(55)	(103)	(106)
Cost of sales	(48)	(55)	(103)	(106)
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	0	0	0	0
Intercompany interest (income) expense, net	0	0	0	0
Loss on extinguishment of debt				0
Other non-operating expense (income), net	0	0	0	0
(Loss) income before tax and earnings from unconsolidated entities	0	0	0	0
Income tax expense (benefit)	0	0	0	0
Loss before earnings from unconsolidated entities	0	0	0	0
Earnings from unconsolidated entities, net of taxes	(51)	74	(37)	91
Net loss	(51)		(37)
Net income attributable to noncontrolling interest	0		0
Net (loss) income attributable to Hexion Inc.	(51)	74	(37)	91
Comprehensive (loss) income attributable to Hexion Inc.	$ (51)	$ 77	$ (51)	$ 83