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postemployment plans and foreign benefit plans. The aggregate liability for the other postemployment plans was $107 million and $93 million as of December 31, 2011 and 2010. The expense for the other postemployment plans, as well as the liability and expense associated with the foreign benefit plans, was not material to our results of operations, financial position, or cash flows. 

The amounts recognized in other comprehensive loss related to our postretirement benefit plans, net of tax, for the years ended December 31, 2011, 2010, and 2009 are shown in the following table, which also shows the amounts related to our postretirement benefit plans included in accumulated other comprehensive loss at the end of 2011 and expected to be recognized in net periodic benefit cost, net of tax, during 2012. 

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## Actuarial Assumptions 

The actuarial assumptions used to determine the benefit obligations at December 31 of each year, and to determine the net periodic benefit cost for each subsequent year, were as follows: 

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The decrease in the discount rate from December 31, 2010 to December 31, 2011 resulted in an increase in the projected benefit obligations of our qualified defined benefit pension plans of approximately $3.8 billion at December 31, 2011. The decrease in the discount rate from December 31, 2009 to December 31, 2010 resulted in an increase in the projected benefit obligations of our qualified defined benefit pension plans of approximately $1.7 billion at December 31, 2010. 

The assumed health care cost trend rates have a significant effect on the amounts reported for the retiree medical plans. A one-percentage-point increase or decrease in assumed health care cost trend rates would result in a change in the postretirement benefit obligation of 4.4% and (3.8)% at December 31, 2011, and a change in the 2011 total service and interest cost of 4.8% and (3.7)%. 

The long-term rate of return assumption represents the expected average rate of earnings on the funds invested or to be invested to provide for the benefits included in the benefit obligations. That assumption is based on several factors including historical market index returns, the anticipated long-term asset allocation of plan assets, the historical return data, plan expenses, and the potential to outperform market index returns. 

