Derivative Instruments And Hedging Activities.

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Fixed rate debt

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Number of countries in which Schlumberger conducts business.

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Variable rate debt

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The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount.

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-Name Accounting Principles Board Opinion (APB)

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Fixed interest rate that will be received or paid upon exercise of the interest rate swaption contract.

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The estimated net amount of unrealized gains or losses on foreign currency cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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Total debt and equity financial instruments including: (1) securities held-to-maturity, (2) trading securities, and (3) securities available-for-sale which are intended to be held for less than one year or the normal operating cycle, whichever is longer.

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Aggregate notional amount of foreign currency exchange rate derivatives. Notional amount refers to the number of currency units specified in the foreign currency derivative contract.

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Aggregate notional amount of interest rate derivatives, which relates to the currency amount specified in the interest rate derivative instruments.

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Derivative Instruments and Hedging Activities (Details 4) (USD $)	9 Months Ended
	Sep. 30, 2011 Year Country	Sep. 30, 2009 3.00% Guaranteed Notes due 2013 [Member]	Sep. 30, 2009 3.00% Guaranteed Notes due 2013 [Member] Fixed Rate Debt [Member]	Sep. 30, 2009 3.00% Guaranteed Notes due 2013 [Member] Floating Rate Debt [Member]
Derivative Instruments and Hedging Activities (Textual) [Abstract]
Number of countries in which Schlumberger conducts business	80
Recognized a cumulative net gain in Equity relating to revaluation of foreign currency forward contracts and foreign currency options designated as cash flow hedges	$ 74,000,000
Contracts outstanding in various foreign currencies (US dollar equivalent)	7,400,000,000
Fixed rate debt aggregate, after taking into account the effects of the interest rate swaps	8,000,000,000
Variable rate debt aggregate, after taking into account the effects of the interest rate swaps	3,400,000,000
Short-term investments and Fixed income investments, held to maturity	4,600,000,000
Derivative [Line Items]
Notional amount of interest rate swap		450,000,000
Notes relating to interest rate swap		$ 450,000,000
Derivative swap interest rate			3.00%	0.765%