Consolidated Statements of Income (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Net sales	$ 7,335us-gaap_SalesRevenueGoodsNet	$ 8,050us-gaap_SalesRevenueGoodsNet	$ 8,380us-gaap_SalesRevenueGoodsNet
Other revenues	69us-gaap_OtherSalesRevenueNet	32us-gaap_OtherSalesRevenueNet	113us-gaap_OtherSalesRevenueNet
Net revenues	7,404us-gaap_SalesRevenueNet	8,082us-gaap_SalesRevenueNet	8,493us-gaap_SalesRevenueNet
Cost of sales	(4,906)us-gaap_CostOfGoodsAndServicesSold	(5,468)us-gaap_CostOfGoodsAndServicesSold	(5,710)us-gaap_CostOfGoodsAndServicesSold
Gross profit	2,498us-gaap_GrossProfit	2,614us-gaap_GrossProfit	2,783us-gaap_GrossProfit
Selling, general and administrative	(927)	(1,066)	(1,166)
Research and development	(1,520)us-gaap_ResearchAndDevelopmentExpense	(1,816)us-gaap_ResearchAndDevelopmentExpense	(2,413)us-gaap_ResearchAndDevelopmentExpense
Other income and expenses, net	207stm_OtherIncomeAndExpensesNet	95stm_OtherIncomeAndExpensesNet	91stm_OtherIncomeAndExpensesNet
Impairment, restructuring charges and other related closure costs	(90)	(292)	(1,376)
Operating income (loss)	168us-gaap_OperatingIncomeLoss	(465)us-gaap_OperatingIncomeLoss	(2,081)us-gaap_OperatingIncomeLoss
Interest expense, net	(18)us-gaap_InterestIncomeExpenseNet	(5)us-gaap_InterestIncomeExpenseNet	(35)us-gaap_InterestIncomeExpenseNet
Income (loss) on equity-method investments	(43)	(122)	(24)
Gain (loss) on financial instruments, net	(1)stm_GainLossOnFinancialInstrumentsNet		3stm_GainLossOnFinancialInstrumentsNet
Income (loss) before income taxes and noncontrolling interest	106	(592)	(2,137)
Income tax benefit (expense)	23us-gaap_IncomeTaxExpenseBenefit	(37)us-gaap_IncomeTaxExpenseBenefit	(51)us-gaap_IncomeTaxExpenseBenefit
Net income (loss)	129us-gaap_ProfitLoss	(629)us-gaap_ProfitLoss	(2,188)us-gaap_ProfitLoss
Net loss (income) attributable to noncontrolling interest	(1)	129	1,030
Net income (loss) attributable to parent company	$ 128us-gaap_NetIncomeLoss	$ (500)us-gaap_NetIncomeLoss	$ (1,158)us-gaap_NetIncomeLoss
Earnings per share (Basic) attributable to parent company stockholders	$ 0.14us-gaap_EarningsPerShareBasic	$ (0.56)us-gaap_EarningsPerShareBasic	$ (1.31)us-gaap_EarningsPerShareBasic
Earnings per share (Diluted) attributable to parent company stockholders	$ 0.14us-gaap_EarningsPerShareDiluted	$ (0.56)us-gaap_EarningsPerShareDiluted	$ (1.31)us-gaap_EarningsPerShareDiluted

This item represents the net total realized and unrealized gain (loss) included in earnings for the period as a result of selling or holding marketable securities categorized as trading, available-for-sale, or held-to-maturity, including the unrealized holding gain or loss of held-to-maturity securities transferred to the trading security category and the cumulative unrealized gain or loss which was included in other comprehensive income (a separate component of shareholders' equity) for available-for-sale securities transferred to trading securities during the period. Additionally, this item would include any gains or losses realized during the period from the sale of investments accounted for under the cost method of accounting and losses recognized for other than temporary impairments of the subject investments. Finally, this item would also include aggregate net gain and losses (whether realized or unrealized) on all derivative instruments held for trading purposes whether or not settled physically.

No definition available.