Operating Segments Operating Segments Level 4 - (Details) - Reconciliation of Segment EBITDA to Net Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Segment EBITDA	$ 60	$ 59	$ 112	$ 114
Non-cash charges	0	11	(3)	29
Unrealized gains from pension liability	13	0	13	0
Restructuring and other costs	(5)	(10)	(9)	(14)
Reorganization Items	(2)	(70)	(7)	(70)
Interest expense, net	(20)	(41)	(39)	(117)
Income Tax Expense (Benefit)	5	(13)	(5)	(21)
Depreciation and amortization	(39)	(42)	(76)	(83)
Net Income (Loss)	12	(106)	(14)	(162)
Silicones [Member]
Segment Reporting Information [Line Items]
Segment EBITDA	60	67	112	125
Quartz [Member]
Segment Reporting Information [Line Items]
Segment EBITDA	9	5	20	12
Corporate Segment [Member]
Segment Reporting Information [Line Items]
Segment EBITDA	(9)	(13)	(20)	(23)
MPM Inc [Member]
Segment Reporting Information [Line Items]
Segment EBITDA	60	59	113	114
Non-cash charges	0	11	(4)	29
Unrealized gains from pension liability	13	0	13	0
Restructuring and other costs	(5)	(10)	(9)	(14)
Reorganization Items	(2)	(70)	(7)	(70)
Interest expense, net	(20)	(41)	(39)	(117)
Income Tax Expense (Benefit)	5	(13)	(5)	(21)
Depreciation and amortization	(39)	(42)	(76)	(83)
Net Income (Loss)	12	(106)	(14)	(162)
MPM Inc [Member] | Silicones [Member]
Segment Reporting Information [Line Items]
Segment EBITDA	60	67	112	125
MPM Inc [Member] | Quartz [Member]
Segment Reporting Information [Line Items]
Segment EBITDA	9	5	20	12
MPM Inc [Member] | Corporate Segment [Member]
Segment Reporting Information [Line Items]
Segment EBITDA	$ (9)	$ (13)	$ (19)	$ (23)