Condensed Consolidating Financial Information (Schedule of Condensed Consolidating Statement of Comprehensive (Loss) Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Net sales	$ 808.4	$ 745.6	$ 1,327.6	$ 1,481.5
Cost of goods sold	702.0	564.5	1,164.5	1,186.4
Gross profit	106.4	181.1	163.1	295.1
Marketing and administration	85.6	94.0	170.3	187.0
Research and development	18.3	21.8	38.4	42.8
Restructuring and impairment charges	1.8	13.6	5.3	13.8
Insurance recovery	0	0	(4.0)	0
Operating income (loss)	0.7	51.7	(46.9)	51.5
Interest expense	44.6	21.2	72.3	30.2
Interest income	(1.1)	(0.9)	(1.9)	(1.8)
Other, net	2.3	(15.3)	2.5	(17.3)
Total non-operating expense (income)	45.8	5.0	72.9	11.1
(Loss) income before income taxes and equity in earnings (loss) of joint venture	(45.1)	46.7	(119.8)	40.4
Income tax expense (benefit)	14.3	0.9	31.3	(13.4)
(Loss) income before equity in earnings (loss) of joint venture	(59.4)	45.8	(151.1)	53.8
Investment in subsidiary earnings (loss)	0	0	0	0
(Loss) equity in earnings of joint venture, net of tax	(0.6)	2.0	(1.8)	3.3
Net (loss) income	(60.0)	47.8	(152.9)	57.1
Net income attributable to noncontrolling interests	(1.3)	(0.5)	(0.4)	(14.3)
Net (loss) income attributable to MEMC stockholders	(61.3)	47.3	(153.3)	42.8
Comprehensive (loss) income	(74.4)	42.3	(171.6)	102.1
Less: comprehensive income attributable to noncontrolling interests	0.7	3.6	0.3	18.6
Comprehensive (loss) income attributable to MEMC stockholders	(75.1)	38.7	(171.9)	83.5
MEMC, Inc. [Member]
Net sales	176.7	232.1	355.4	440.4
Cost of goods sold	188.3	236.2	382.0	452.3
Gross profit	(11.6)	(4.1)	(26.6)	(11.9)
Marketing and administration	28.4	37.1	61.3	81.8
Research and development	12.4	15.6	25.6	30.8
Restructuring and impairment charges	(4.4)	6.5	(0.8)	6.7
Insurance recovery			0
Operating income (loss)	(48.0)	(63.3)	(112.7)	(131.2)
Interest expense	11.9	11.1	23.4	14.3
Interest income	(0.1)	(0.1)	(0.1)	(0.2)
Other, net	(14.7)	(12.3)	(28.4)	(22.7)
Total non-operating expense (income)	(2.9)	(1.3)	(5.1)	(8.6)
(Loss) income before income taxes and equity in earnings (loss) of joint venture	(45.1)	(62.0)	(107.6)	(122.6)
Income tax expense (benefit)	(24.4)	(30.5)	(46.6)	(44.7)
(Loss) income before equity in earnings (loss) of joint venture	(20.7)	(31.5)	(61.0)	(77.9)
Investment in subsidiary earnings (loss)	(40.6)	78.9	(92.3)	120.8
(Loss) equity in earnings of joint venture, net of tax	0	(0.1)	0	(0.1)
Net (loss) income	(61.3)	47.3	(153.3)	42.8
Net income attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to MEMC stockholders	(61.3)	47.3	(153.3)	42.8
Comprehensive (loss) income	(62.4)	47.3	(151.9)	42.6
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive (loss) income attributable to MEMC stockholders	(62.4)	47.3	(151.9)	42.6
Guarantor Subsidiaries [Member]
Net sales	228.6	111.4	329.6	252.2
Cost of goods sold	141.0	99.2	329.1	244.6
Gross profit	87.6	12.2	0.5	7.6
Marketing and administration	28.6	20.5	52.5	43.0
Research and development	4.0	2.1	7.6	4.2
Restructuring and impairment charges	4.0	0.4	4.0	0.4
Insurance recovery			0
Operating income (loss)	51.0	(10.8)	(63.6)	(40.0)
Interest expense	5.3	0.2	6.2	0.6
Interest income	0	(0.2)	0	(0.4)
Other, net	4.5	(2.1)	(0.6)	(1.3)
Total non-operating expense (income)	9.8	(2.1)	5.6	(1.1)
(Loss) income before income taxes and equity in earnings (loss) of joint venture	41.2	(8.7)	(69.2)	(38.9)
Income tax expense (benefit)	40.2	13.2	65.5	0.9
(Loss) income before equity in earnings (loss) of joint venture	1.0	(21.9)	(134.7)	(39.8)
Investment in subsidiary earnings (loss)	(81.4)	95.2	(71.6)	112.4
(Loss) equity in earnings of joint venture, net of tax	0	0	0	0
Net (loss) income	(80.4)	73.3	(206.3)	72.6
Net income attributable to noncontrolling interests	(0.4)	0.1	(0.4)	0.1
Net (loss) income attributable to MEMC stockholders	(80.8)	73.4	(206.7)	72.7
Comprehensive (loss) income	(80.4)	73.3	(206.3)	72.6
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive (loss) income attributable to MEMC stockholders	(80.4)	73.3	(206.3)	72.6
Non-Guarantor Subsidiaries [Member]
Net sales	893.5	1,057.5	1,621.5	1,947.6
Cost of goods sold	889.7	876.9	1,440.7	1,627.0
Gross profit	3.8	180.6	180.8	320.6
Marketing and administration	28.6	36.4	56.5	62.2
Research and development	1.9	4.1	5.2	7.8
Restructuring and impairment charges	2.2	6.7	2.1	6.7
Insurance recovery			(4.0)
Operating income (loss)	(28.9)	133.4	121.0	243.9
Interest expense	27.4	9.5	42.7	16.0
Interest income	(1.0)	(0.2)	(1.8)	(1.9)
Other, net	11.6	(5.4)	25.4	0.1
Total non-operating expense (income)	38.0	3.9	66.3	14.2
(Loss) income before income taxes and equity in earnings (loss) of joint venture	(66.9)	129.5	54.7	229.7
Income tax expense (benefit)	(1.3)	19.5	11.1	31.3
(Loss) income before equity in earnings (loss) of joint venture	(65.6)	110.0	43.6	198.4
Investment in subsidiary earnings (loss)	0	0	0	0
(Loss) equity in earnings of joint venture, net of tax	(0.6)	2.1	(1.8)	3.4
Net (loss) income	(66.2)	112.1	41.8	201.8
Net income attributable to noncontrolling interests	(0.9)	(0.6)	0	(14.4)
Net (loss) income attributable to MEMC stockholders	(67.1)	111.5	41.8	187.4
Comprehensive (loss) income	(79.5)	106.6	21.7	247.0
Less: comprehensive income attributable to noncontrolling interests	0.7	3.6	0.3	18.6
Comprehensive (loss) income attributable to MEMC stockholders	(80.2)	103.0	21.4	228.4
Consolidating Adjustments [Member]
Net sales	(490.4)	(655.4)	(978.9)	(1,158.7)
Cost of goods sold	(517.0)	(647.8)	(987.3)	(1,137.5)
Gross profit	26.6	(7.6)	8.4	(21.2)
Marketing and administration	0	0	0	0
Research and development	0	0	0	0
Restructuring and impairment charges	0	0	0	0
Insurance recovery			0
Operating income (loss)	26.6	(7.6)	8.4	(21.2)
Interest expense	0	0.4	0	(0.7)
Interest income	0	(0.4)	0	0.7
Other, net	0.9	4.5	6.1	6.6
Total non-operating expense (income)	0.9	4.5	6.1	6.6
(Loss) income before income taxes and equity in earnings (loss) of joint venture	25.7	(12.1)	2.3	(27.8)
Income tax expense (benefit)	(0.2)	(1.3)	1.3	(0.9)
(Loss) income before equity in earnings (loss) of joint venture	25.9	(10.8)	1.0	(26.9)
Investment in subsidiary earnings (loss)	122.0	(174.1)	163.9	(233.2)
(Loss) equity in earnings of joint venture, net of tax	0	0	0	0
Net (loss) income	147.9	(184.9)	164.9	(260.1)
Net income attributable to noncontrolling interests	0	0	0	0
Net (loss) income attributable to MEMC stockholders	147.9	(184.9)	164.9	(260.1)
Comprehensive (loss) income	147.9	(184.9)	164.9	(260.1)
Less: comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive (loss) income attributable to MEMC stockholders	$ 147.9	$ (184.9)	$ 164.9	$ (260.1)