Note 6: Available-for-Sale Investments

Available-for-sale investments as of June 30, 2012 and December 31, 2011 were as follows:

In the preceding table, government bonds include bonds issued or deemed to be guaranteed by government entities. Government bonds include instruments such as U.S. Treasury securities, U.S. agency securities, and non-U.S. government obligations as of June 30, 2012 and December 31, 2011.

The amortized cost and fair value of available-for-sale debt investments as of June 30, 2012, by contractual maturity, were as follows:

Instruments not due at a single maturity date in the preceding table include asset-backed securities and money market fund deposits.

We sold available-for-sale investments for proceeds of $274 million in the second quarter of 2012 and $607 million in the first half of 2012 ($1.2 billion in the second quarter of 2011 and $8.8 billion in the first half of 2011). The gross realized gains on sales of available-for-sale investments were $34 million in the second quarter of 2012 and $36 million in the first half of 2012 ($36 million in the second quarter of 2011 and $64 million in the first half of 2011) and were primarily related to our sales of marketable equity securities. We determine the cost of an investment sold on an average cost basis at the individual security level. Impairment charges recognized on available-for-sale investments were $35 million in the second quarter of 2012.

The before-tax net unrealized holding gains (losses) on available-for-sale investments that have been included in other comprehensive income (loss) and the before-tax net gains (losses) reclassified from accumulated other comprehensive income (loss) into earnings were as follows: