| Amortized cost, gross unrealized gains, gross unrealized losses and estimated fair values of available-for-sale investments by type of security |
| | | | | | | | | | | | | | | | | Type of security as of December 31, 2011 | Amortized cost | | Gross unrealized gains | | Gross unrealized losses | | Estimated fair value | U.S. Treasury securities | $ | 3,878 |
| | $ | 68 |
| | $ | — |
| | $ | 3,946 |
| Other government-related debt securities: | | | | | | | | U.S. | 1,548 |
| | 23 |
| | — |
| | 1,571 |
| Foreign and other | 441 |
| | 9 |
| | — |
| | 450 |
| Corporate debt securities: | | | | | | | | Financial | 2,493 |
| | 30 |
| | (15 | ) | | 2,508 |
| Industrial | 3,077 |
| | 79 |
| | (10 | ) | | 3,146 |
| Other | 280 |
| | 9 |
| | — |
| | 289 |
| Residential mortgage-backed securities | 518 |
| | 3 |
| | (3 | ) | | 518 |
| Other mortgage- and asset-backed securities | 1,271 |
| | 3 |
| | (7 | ) | | 1,267 |
| Money market mutual funds | 6,266 |
| | — |
| | — |
| | 6,266 |
| Total interest-bearing securities | 19,772 |
| | 224 |
| | (35 | ) | | 19,961 |
| Equity securities | 42 |
| | — |
| | — |
| | 42 |
| Total available-for-sale investments | $ | 19,814 |
| | $ | 224 |
| | $ | (35 | ) | | $ | 20,003 |
|
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 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 Consolidated Balance Sheets were as follows as of December 31, 2012 and 2011 (in millions): | | | | | | | | | Classification in the Consolidated Balance Sheets | 2012 | | 2011 | Cash and cash equivalents | $ | 2,887 |
| | $ | 6,266 |
| Marketable securities | 20,804 |
| | 13,695 |
| Other assets — noncurrent | 54 |
| | 42 |
| Total available-for-sale investments | $ | 23,745 |
| | $ | 20,003 |
|
|
| 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 as of December 31, 2012 and 2011 (in millions): | | | | | | | | | Contractual maturity | 2012 | | 2011 | Maturing in one year or less | $ | 7,175 |
| | $ | 6,791 |
| Maturing after one year through three years | 5,014 |
| | 5,855 |
| Maturing after three years through five years | 6,286 |
| | 5,379 |
| Maturing after five years through ten years | 1,620 |
| | 151 |
| Mortgage- and asset-backed securities | 3,596 |
| | 1,785 |
| Total interest-bearing securities | $ | 23,691 |
| | $ | 19,961 |
|
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