expenses into U.S. dollars for consolidated reporting, certain foreign subsidiaries use excess cash to purchase U.S. dollar denominated available-for- sale investments. The variable future cash flows associated with the purchase and subsequent sale of these U.S. dollar denominated securities at non-U.S. dollar functional currency subsidiaries creates a foreign currency exposure that qualifies for hedge accounting under the accounting standards for derivatives and hedging. We utilize forward contracts and options to partially, or entirely, hedge the variability of the forecasted future purchases and sales of these U.S. dollar investments. This has the effect of partially offsetting the year-over-year foreign currency translation impact on net earnings in the period the investments are sold. Hedges of available-for-sale investments are accounted for as cash flow hedges. The fair value of instruments used in this manner at May 31, 2011 was $1 million in assets and $21 million in liabilities. At May 31, 2010, the fair value was $78 million in assets. The effective portion of the changes in fair value of these instruments is reported in OCI and reclassified into earnings in other (income), net in the period during which the hedged available-for-sale investment is sold and affects earnings. Any ineffective portion, which was not material for any period presented, is immediately recognized in earnings as a component of other (income), net. 

We estimate that the combination of translation of foreign currency-denominated profits from our international businesses and the year-over-year change in foreign currency related net gains included in other (income), net had net (detriment) benefit on our income before income taxes of approximately $(33) million and $34 million for the years ended May 31, 2011 and 2010. 

Refer to Note 17 — Risk Management and Derivatives in the accompanying Notes to the Consolidated Financial Statements for additional quantitative detail. 

Net investments in foreign subsidiaries 

We are also exposed to the impact of foreign exchange fluctuations on our investments in wholly-owned foreign subsidiaries denominated in a currency other than the U.S. dollar, which could adversely impact the U.S. dollar value of these investments and therefore the value of future repatriated earnings. We hedge certain net investment positions in Euro-functional currency foreign subsidiaries to mitigate the effects of foreign exchange fluctuations on net investments with the effect of preserving the value of future repatriated earnings. In accordance with the accounting standards for derivatives and hedging, the effective portion of the change in fair value of the forward contracts designated as net investment hedges is recorded in the cumulative translation adjustment component of accumulated other comprehensive income. Any ineffective portion, which was not material for any period presented, is immediately recognized in earnings as a component of other (income), net. To minimize credit risk, we have structured these net investment hedges to be generally less than six months in duration. Upon maturity, the hedges are settled based on the current