| Cash Equivalents and Marketable Securities |
| | | | | | | | | | | | | | | | | | January 25, 2015 | | Amortized Cost | | Unrealized Gain | | Unrealized Loss | | Estimated Fair Value | | (In thousands) | Corporate debt securities | $ | 2,184,925 |
| | $ | 2,600 |
| | $ | (1,214 | ) | | $ | 2,186,311 |
| Debt securities of United States government agencies | 749,630 |
| | 917 |
| | (227 | ) | | 750,320 |
| Debt securities issued by United States Treasury | 533,673 |
| | 2,694 |
| | (3 | ) | | 536,364 |
| Asset-backed securities | 453,088 |
| | 125 |
| | (329 | ) | | 452,884 |
| Mortgage backed securities issued by United States government-sponsored enterprises | 274,366 |
| | 4,589 |
| | (850 | ) | | 278,105 |
| Money market funds | 132,495 |
| | — |
| | — |
| | 132,495 |
| Foreign government bonds | 84,800 |
| | 121 |
| | (5 | ) | | 84,916 |
| Total | $ | 4,412,977 |
| | $ | 11,046 |
| | $ | (2,628 | ) | | $ | 4,421,395 |
| Classified as: | | | | | | | | Cash equivalents | | | | | | | $ | 294,710 |
| Marketable securities | | | | | | | 4,126,685 |
| Total | | | | | | | $ | 4,421,395 |
|
| | | | | | | | | | | | | | | | | | January 26, 2014 | | Amortized Cost | | Unrealized Gain | | Unrealized Loss | | Estimated Fair Value | | (In thousands) | Corporate debt securities | $ | 1,762,833 |
| | $ | 1,837 |
| | $ | (945 | ) | | $ | 1,763,725 |
| Debt securities of United States government agencies | 1,012,740 |
| | 848 |
| | (261 | ) | | 1,013,327 |
| Debt securities issued by United States Treasury | 495,889 |
| | 621 |
| | (57 | ) | | 496,453 |
| Money market funds | 307,865 |
| | — |
| | — |
| | 307,865 |
| Asset-backed securities | 258,017 |
| | 15 |
| | (315 | ) | | 257,717 |
| Mortgage backed securities issued by United States government-sponsored enterprises | 185,594 |
| | 3,837 |
| | (725 | ) | | 188,706 |
| Foreign government bonds | 64,955 |
| | 20 |
| | (120 | ) | | 64,855 |
| Total | $ | 4,087,893 |
| | $ | 7,178 |
| | $ | (2,423 | ) | | $ | 4,092,648 |
| Classified as: | | | | | | | | Cash equivalents | | | | | | | $ | 572,425 |
| Marketable securities | | | | | | | 3,520,223 |
| Total | | | | | | | $ | 4,092,648 |
|
The following table provides the breakdown of the investments that were in a continuous unrealized loss position at January 25, 2015: | | | | | | | | | | | | | | | | | | | | | | | | | | Less than 12 Months | | 12 Months or Greater | | Total | | Fair Value | | Gross Unrealized Losses | | Fair Value | | Gross Unrealized Losses | | Fair Value | | Gross Unrealized Losses | | (In thousands) | Corporate debt securities | $ | 709,392 |
| | $ | (1,199 | ) | | $ | 10,085 |
| | $ | (15 | ) | | $ | 719,477 |
| | $ | (1,214 | ) | Mortgage backed securities issued by United States government-sponsored enterprises | 81,245 |
| | (639 | ) | | 21,314 |
| | (211 | ) | | 102,559 |
| | (850 | ) | Debt securities of United States Treasury | 10,026 |
| | (3 | ) | | — |
| | — |
| | 10,026 |
| | (3 | ) | Debt securities issued by United States government agencies | 246,480 |
| | (227 | ) | | — |
| | — |
| | 246,480 |
| | (227 | ) | Asset-backed securities | 306,066 |
| | (323 | ) | | 4,476 |
| | (6 | ) | | 310,542 |
| | (329 | ) | Foreign government bonds | 11,008 |
| | (5 | ) | | — |
| | — |
| | 11,008 |
| | (5 | ) | Total | $ | 1,364,217 |
| | $ | (2,396 | ) | | $ | 35,875 |
| | $ | (232 | ) | | $ | 1,400,092 |
| | $ | (2,628 | ) |
|
| Schedule of Cash Equivalents and Marketable Securities Available for Sale |
| | | | | | | | | | | | | | | | | | January 25, 2015 | | January 26, 2014 | | Amortized Cost | | Estimated Fair Value | | Amortized Cost | | Estimated Fair Value | | (In thousands) | Less than one year | $ | 1,570,233 |
| | $ | 1,570,622 |
| | $ | 1,883,132 |
| | $ | 1,883,753 |
| Due in 1 - 5 years | 2,719,852 |
| | 2,725,945 |
| | 2,114,289 |
| | 2,117,387 |
| Mortgage-backed securities issued by government-sponsored enterprises not due at a single maturity date | 122,893 |
| | 124,828 |
| | 90,472 |
| | 91,508 |
| Total | $ | 4,412,978 |
| | $ | 4,421,395 |
| | $ | 4,087,893 |
| | $ | 4,092,648 |
|
|