| 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 September 30, 2012 | | Amortized cost | | Gross unrealized gains | | Gross unrealized losses | | Estimated fair value | U.S. Treasury securities | | $ | 3,936 |
| | $ | 24 |
| | $ | — |
| | $ | 3,960 |
| Other government-related debt securities: | | | | | | | | | Obligations of U.S. government agencies and
FDIC-guaranteed bank debt | | 1,180 |
| | 18 |
| | — |
| | 1,198 |
| Foreign and other | | 1,656 |
| | 56 |
| | — |
| | 1,712 |
| Corporate debt securities: | | | | | | | | | Financial | | 3,158 |
| | 99 |
| | (1 | ) | | 3,256 |
| Industrial | | 4,208 |
| | 114 |
| | (4 | ) | | 4,318 |
| Other | | 420 |
| | 12 |
| | — |
| | 432 |
| Residential mortgage-backed securities | | 1,834 |
| | 9 |
| | (7 | ) | | 1,836 |
| Other mortgage- and asset-backed securities | | 2,062 |
| | 10 |
| | (6 | ) | | 2,066 |
| Money market mutual funds | | 4,000 |
| | — |
| | — |
| | 4,000 |
| Other short-term interest-bearing securities | | 2,105 |
| | — |
| | — |
| | 2,105 |
| Total debt security investments | | 24,559 |
| | 342 |
| | (18 | ) | | 24,883 |
| Equity securities | | 50 |
| | 2 |
| | — |
| | 52 |
| Total available-for-sale investments | | $ | 24,609 |
| | $ | 344 |
| | $ | (18 | ) | | $ | 24,935 |
|
| | | | | | | | | | | | | | | | | | 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: | | | | | | | | | Obligations of U.S. government agencies and
FDIC-guaranteed bank debt | | 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 debt security investments | | 19,772 |
| | 224 |
| | (35 | ) | | 19,961 |
| Equity securities | | 42 |
| | — |
| | — |
| | 42 |
| Total available-for-sale investments | | $ | 19,814 |
| | $ | 224 |
| | $ | (35 | ) | | $ | 20,003 |
|
|
| 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 | | September 30,
2012 | | December 31,
2011 | Cash and cash equivalents | | $ | 5,332 |
| | $ | 6,266 |
| Marketable securities | | 19,551 |
| | 13,695 |
| Other assets — noncurrent | | 52 |
| | 42 |
| Total available-for-sale investments | | $ | 24,935 |
| | $ | 20,003 |
|
|
| Fair values of available-for-sale debt security investments by contractual maturity |
The fair values of available-for-sale debt 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 | | September 30,
2012 | | December 31,
2011 | Maturing in one year or less | | $ | 8,501 |
| | $ | 6,791 |
| Maturing after one year through three years | | 4,998 |
| | 5,855 |
| Maturing after three years through five years | | 5,861 |
| | 5,379 |
| Maturing after five years through ten years | | 1,621 |
| | 151 |
| Mortgage- and asset-backed securities | | 3,902 |
| | 1,785 |
| Total debt security investments | | $ | 24,883 |
| | $ | 19,961 |
|
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