Condensesd Consolidated Statements of Equity - 6 months ended Jun. 30, 2015 - USD ($) $ in Millions	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated deficit	MPM Inc [Member]	MPM Inc [Member] Common stock	MPM Inc [Member] Additional paid-in capital	MPM Inc [Member] Accumulated other comprehensive income (loss)	MPM Inc [Member] Accumulated deficit
Balance at Dec. 31, 2014	$ 769	$ 0	$ 857	$ (28)	$ (60)	$ 769	$ 0	$ 857	$ (28)	$ (60)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Allocated Share-based Compensation Expense	1	0	1	0	0	1	0	1	0	0
Net Income (Loss)	(14)	0	0	0		(14)	0	0	0
Other Comprehensive Income (Loss), Net of Tax	(39)	0	0	(39)	0	(39)	0	0		0
Proceeds from Issuance of Common Stock	1	0	1	0	0	0
Balance at Jun. 30, 2015	$ 718	$ 0	$ 859	$ (67)	$ (74)	$ 717	$ 0	$ 858	$ (67)	$ (74)