Guarantor Non-Guarantor Subsidiary Financial Information (Details) - Consolidating Balance Sheets - USD ($) $ in Millions	Jul. 01, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents (including restricted cash of $0 and $15, respectively)		$ 96		$ 128	$ 130		$ 115
Accounts receivable, net		499		412
Intercompany accounts receivable		0		0
Intercompany loans receivable—current portion		0		0
Finished and in-process goods		242		240
Raw materials and supplies		109		94
Other current assets		69		57
Total current assets		(1,015)		(931)
Investment in unconsolidated entities		20		19
Deferred income taxes				0
Other assets, net		42		34
Intercompany loans receivable		0		0
Property and equipment, net		827		841
Operating Lease, Right-of-Use Asset		95		0
Goodwill		108		109
Other intangible assets, net		24		27
Total assets		2,131		1,961
Current liabilities
Accounts payable		293		384
Intercompany accounts payable		0		0
Debt payable within one year		438		3,716
Intercompany loans payable within one year		0		0
Interest payable		7		82
Income taxes payable		6		5
Accrued payroll and incentive compensation		38		52
Operating Lease, Liability, Current		21		0
Financing fees payable		104		0
Other current liabilities		106		106
Total current liabilities		1,013		4,345
Long-term liabilities
Liabilities Subject to Compromise		3,672		0
Long-term debt	$ 1,718	90		99
Intercompany loans payable		0		0
Accumulated losses of unconsolidated subsidiaries in excess of investment		0		0
Long-term pension and post employment benefit obligations		184		221
Deferred income taxes		15		15
Operating Lease, Liability, Noncurrent		74		0
Other long-term liabilities		164		195
Total liabilities		5,212		4,875
Total Hexion Inc. shareholder’s deficit		(3,080)		(2,912)
Noncontrolling interest		(1)		(2)
Total deficit		(3,081)	$ (2,966)	(2,914)	(2,777)	$ (2,740)	(2,742)
Total liabilities and deficit		2,131		1,961
Hexion Inc. [Member]
Current assets
Cash and cash equivalents (including restricted cash of $0 and $15, respectively)		13		20	42		13
Accounts receivable, net		143		98
Intercompany accounts receivable		56		40
Intercompany loans receivable—current portion		248		82
Finished and in-process goods		99		100
Raw materials and supplies		44		36
Other current assets		32		28
Total current assets		(635)		(404)
Investment in unconsolidated entities		134		134
Deferred income taxes				0
Other assets, net		10		10
Intercompany loans receivable		725		1,114
Property and equipment, net		353		363
Operating Lease, Right-of-Use Asset		42
Goodwill		52		53
Other intangible assets, net		17		19
Total assets		1,968		2,097
Current liabilities
Accounts payable		79		126
Intercompany accounts payable		82		66
Debt payable within one year		9		3,563
Intercompany loans payable within one year		0		101
Interest payable		1		81
Income taxes payable		2		3
Accrued payroll and incentive compensation		10		22
Operating Lease, Liability, Current		11
Financing fees payable		104
Other current liabilities		63		61
Total current liabilities		361		4,023
Long-term liabilities
Liabilities Subject to Compromise		3,671
Long-term debt		47		52
Intercompany loans payable		369		0
Accumulated losses of unconsolidated subsidiaries in excess of investment		476		781
Long-term pension and post employment benefit obligations		0		34
Deferred income taxes		11		2
Operating Lease, Liability, Noncurrent		31
Other long-term liabilities		82		117
Total liabilities		5,048		5,009
Total Hexion Inc. shareholder’s deficit		(3,080)		(2,912)
Noncontrolling interest		0		0
Total deficit		(3,080)		(2,912)
Total liabilities and deficit		1,968		2,097
Combined Subsidiary Guarantors [Member]
Current assets
Cash and cash equivalents (including restricted cash of $0 and $15, respectively)		0		0	0		0
Accounts receivable, net		0		0
Intercompany accounts receivable		1		0
Intercompany loans receivable—current portion		0		0
Finished and in-process goods		0		0
Raw materials and supplies		0		0
Other current assets		0		0
Total current assets		(1)		0
Investment in unconsolidated entities		14		12
Deferred income taxes				0
Other assets, net		7		7
Intercompany loans receivable		0		0
Property and equipment, net		0		0
Operating Lease, Right-of-Use Asset		0
Goodwill		0		0
Other intangible assets, net		0		0
Total assets		22		19
Current liabilities
Accounts payable		0		0
Intercompany accounts payable		0		0
Debt payable within one year		0		0
Intercompany loans payable within one year		0		0
Interest payable		0		0
Income taxes payable		0		0
Accrued payroll and incentive compensation		0		0
Operating Lease, Liability, Current		0
Financing fees payable		0
Other current liabilities		0		0
Total current liabilities		0		0
Long-term liabilities
Liabilities Subject to Compromise		1
Long-term debt		0		0
Intercompany loans payable		0		0
Accumulated losses of unconsolidated subsidiaries in excess of investment		148		146
Long-term pension and post employment benefit obligations		0		0
Deferred income taxes		0		0
Operating Lease, Liability, Noncurrent		0
Other long-term liabilities		0		0
Total liabilities		149		146
Total Hexion Inc. shareholder’s deficit		(127)		(127)
Noncontrolling interest		0		0
Total deficit		(127)		(127)
Total liabilities and deficit		22		19
Combined Non-Guarantor Subsidiaries [Member]
Current assets
Cash and cash equivalents (including restricted cash of $0 and $15, respectively)		83		108	88		102
Accounts receivable, net		356		314
Intercompany accounts receivable		81		66
Intercompany loans receivable—current portion		0		101
Finished and in-process goods		143		140
Raw materials and supplies		65		58
Other current assets		37		29
Total current assets		(765)		(816)
Investment in unconsolidated entities		20		19
Deferred income taxes				0
Other assets, net		25		17
Intercompany loans receivable		369		0
Property and equipment, net		474		478
Operating Lease, Right-of-Use Asset		53
Goodwill		56		56
Other intangible assets, net		7		8
Total assets		1,769		1,394
Current liabilities
Accounts payable		214		258
Intercompany accounts payable		56		40
Debt payable within one year		429		153
Intercompany loans payable within one year		248		82
Interest payable		6		1
Income taxes payable		4		2
Accrued payroll and incentive compensation		28		30
Operating Lease, Liability, Current		10
Financing fees payable		0
Other current liabilities		43		45
Total current liabilities		1,038		611
Long-term liabilities
Liabilities Subject to Compromise		0
Long-term debt		43		47
Intercompany loans payable		725		1,114
Accumulated losses of unconsolidated subsidiaries in excess of investment		0		0
Long-term pension and post employment benefit obligations		184		187
Deferred income taxes		4		13
Operating Lease, Liability, Noncurrent		43
Other long-term liabilities		82		78
Total liabilities		2,119		2,050
Total Hexion Inc. shareholder’s deficit		(349)		(654)
Noncontrolling interest		(1)		(2)
Total deficit		(350)		(656)
Total liabilities and deficit		1,769		1,394
Consolidation, Eliminations [Member]
Current assets
Cash and cash equivalents (including restricted cash of $0 and $15, respectively)		0		0	$ 0		$ 0
Accounts receivable, net		0		0
Intercompany accounts receivable		(138)		(106)
Intercompany loans receivable—current portion		(248)		(183)
Finished and in-process goods		0		0
Raw materials and supplies		0		0
Other current assets		0		0
Total current assets		386		289
Investment in unconsolidated entities		(148)		(146)
Deferred income taxes				0
Other assets, net		0		0
Intercompany loans receivable		(1,094)		(1,114)
Property and equipment, net		0		0
Operating Lease, Right-of-Use Asset		0
Goodwill		0		0
Other intangible assets, net		0		0
Total assets		(1,628)		(1,549)
Current liabilities
Accounts payable		0		0
Intercompany accounts payable		(138)		(106)
Debt payable within one year		0		0
Intercompany loans payable within one year		(248)		(183)
Interest payable		0		0
Income taxes payable		0		0
Accrued payroll and incentive compensation		0		0
Operating Lease, Liability, Current		0
Financing fees payable		0
Other current liabilities		0		0
Total current liabilities		(386)		(289)
Long-term liabilities
Liabilities Subject to Compromise		0
Long-term debt		0		0
Intercompany loans payable		(1,094)		(1,114)
Accumulated losses of unconsolidated subsidiaries in excess of investment		(624)		(927)
Long-term pension and post employment benefit obligations		0		0
Deferred income taxes		0		0
Operating Lease, Liability, Noncurrent		0
Other long-term liabilities		0		0
Total liabilities		(2,104)		(2,330)
Total Hexion Inc. shareholder’s deficit		476		781
Noncontrolling interest		0		0
Total deficit		476		781
Total liabilities and deficit		$ (1,628)		$ (1,549)