| Amortized cost, gross unrealized gains, gross unrealized losses and estimated fair values of available-for-sale investments by type of security |
The amortized cost, gross unrealized gains, gross unrealized losses and estimated fair values of available-for-sale investments by type of security were as follows (in millions): | | | | | | | | | | | | | | | | | | Type of security as of March 31, 2013 | | Amortized cost | | Gross unrealized gains | | Gross unrealized losses | | Estimated fair value | U.S. Treasury securities | | $ | 2,698 |
| | $ | 9 |
| | $ | — |
| | $ | 2,707 |
| Other government-related debt securities: | | | | | | | | | U.S. | | 1,013 |
| | 6 |
| | — |
| | 1,019 |
| Foreign and other | | 1,436 |
| | 35 |
| | (5 | ) | | 1,466 |
| Corporate debt securities: | | | | | | | | | Financial | | 3,907 |
| | 72 |
| | (2 | ) | | 3,977 |
| Industrial | | 4,380 |
| | 79 |
| | (2 | ) | | 4,457 |
| Other | | 470 |
| | 9 |
| | — |
| | 479 |
| Residential mortgage-backed securities | | 1,816 |
| | 9 |
| | (8 | ) | | 1,817 |
| Other mortgage- and asset-backed securities | | 1,515 |
| | 2 |
| | (20 | ) | | 1,497 |
| Money market mutual funds | | 1,742 |
| | — |
| | — |
| | 1,742 |
| Other short-term interest-bearing securities | | 1,677 |
| | — |
| | — |
| | 1,677 |
| Total interest-bearing securities | | 20,654 |
| | 221 |
| | (37 | ) | | 20,838 |
| Equity securities | | 55 |
| | 7 |
| | — |
| | 62 |
| Total available-for-sale investments | | $ | 20,709 |
| | $ | 228 |
| | $ | (37 | ) | | $ | 20,900 |
|
| | | | | | | | | | | | | | | | | | Type of security as of December 31, 2012 | | Amortized cost | | Gross unrealized gains | | Gross unrealized losses | | Estimated fair value | U.S. Treasury securities | | $ | 4,443 |
| | $ | 15 |
| | $ | — |
| | $ | 4,458 |
| Other government-related debt securities: | | | | | | | | | U.S. | | 1,018 |
| | 12 |
| | — |
| | 1,030 |
| Foreign and other | | 1,549 |
| | 60 |
| | (1 | ) | | 1,608 |
| Corporate debt securities: | | | | | | | | | Financial | | 3,266 |
| | 96 |
| | (1 | ) | | 3,361 |
| Industrial | | 4,283 |
| | 100 |
| | (3 | ) | | 4,380 |
| Other | | 441 |
| | 11 |
| | — |
| | 452 |
| Residential mortgage-backed securities | | 1,828 |
| | 9 |
| | (8 | ) | | 1,829 |
| Other mortgage- and asset-backed securities | | 1,769 |
| | 7 |
| | (9 | ) | | 1,767 |
| Money market mutual funds | | 2,620 |
| | — |
| | — |
| | 2,620 |
| Other short-term interest-bearing securities | | 2,186 |
| | — |
| | — |
| | 2,186 |
| Total interest-bearing securities | | 23,403 |
| | 310 |
| | (22 | ) | | 23,691 |
| Equity securities | | 52 |
| | 2 |
| | — |
| | 54 |
| Total available-for-sale investments | | $ | 23,455 |
| | $ | 312 |
| | $ | (22 | ) | | $ | 23,745 |
|
|
| Fair values of available-for-sale investments by classification in the Consolidated Balance Sheets |
The fair values of available-for-sale investments by classification in the Condensed Consolidated Balance Sheets were as follows (in millions): | | | | | | | | | | Classification in the Condensed Consolidated Balance Sheets | | March 31,
2013 | | December 31,
2012 | Cash and cash equivalents | | $ | 2,097 |
| | $ | 2,887 |
| Marketable securities | | 18,741 |
| | 20,804 |
| Other assets — noncurrent | | 62 |
| | 54 |
| Total available-for-sale investments | | $ | 20,900 |
| | $ | 23,745 |
|
|
| Fair values of available-for-sale interest-bearing security investments by contractual maturity |
The fair values of available-for-sale interest-bearing security investments by contractual maturity, except for mortgage- and asset- backed securities that do not have a single maturity date, were as follows (in millions): | | | | | | | | | | Contractual maturity | | March 31,
2013 | | December 31,
2012 | Maturing in one year or less | | $ | 3,916 |
| | $ | 7,175 |
| Maturing after one year through three years | | 4,926 |
| | 5,014 |
| Maturing after three years through five years | | 6,919 |
| | 6,286 |
| Maturing after five years through ten years | | 1,763 |
| | 1,620 |
| Mortgage- and asset-backed securities | | 3,314 |
| | 3,596 |
| Total interest-bearing securities | | $ | 20,838 |
| | $ | 23,691 |
|
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