Marketable Securities (Details) - USD ($) $ in Millions | 6 Months Ended | |
Jul. 26, 2015 | Jan. 25, 2015 |
Summary of cash equivalents and marketable securities: | | |
Available-for-sale Securities, Amortized Cost Basis | $ 4,105 | $ 4,413 |
Unrealized Gain | 6 | 11 |
Unrealized Loss | (5) | (3) |
Estimated Fair Value | 4,106 | 4,421 |
Classified as: | | |
Cash equivalents | 36 | 295 |
Marketable securities | 4,070 | 4,126 |
Total cash equivalents and marketable securities | 4,106 | 4,421 |
Amortized Cost | | |
Less than one year | 1,174 | 1,570 |
Due in 1-5 years | 2,812 | 2,720 |
Mortgage-backed securities issued by government-sponsored enterprises not due to a single maturity date | 119 | 123 |
Total | 4,105 | 4,413 |
Estimated Fair Value | | |
Less than one year | 1,174 | 1,571 |
Due in 1-5 years | 2,811 | 2,726 |
Mortgage-backed securities issued by government-sponsored enterprises not due to a single maturity date | 121 | 124 |
Total | 4,106 | 4,421 |
Unrealized Loss Position, Fair Value | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 1,915 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value | 63 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 1,978 | |
Unrealized Loss Position, Aggregate Losses | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (5) | |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 0 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | (5) | |
Net realized gain | | |
Realized Investment Gains | 3 | |
Corporate debt securities | | |
Summary of cash equivalents and marketable securities: | | |
Available-for-sale Securities, Amortized Cost Basis | 1,972 | 2,185 |
Unrealized Gain | 1 | 2 |
Unrealized Loss | (3) | (1) |
Estimated Fair Value | 1,970 | 2,186 |
Classified as: | | |
Total cash equivalents and marketable securities | 1,970 | 2,186 |
Unrealized Loss Position, Fair Value | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 1,098 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value | 40 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 1,138 | |
Unrealized Loss Position, Aggregate Losses | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (3) | |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 0 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | (3) | |
Debt securities of United States government agencies | | |
Summary of cash equivalents and marketable securities: | | |
Available-for-sale Securities, Amortized Cost Basis | 893 | 750 |
Unrealized Gain | 1 | 1 |
Unrealized Loss | (1) | (1) |
Estimated Fair Value | 893 | 750 |
Classified as: | | |
Total cash equivalents and marketable securities | 893 | 750 |
Unrealized Loss Position, Fair Value | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 504 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value | 0 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 504 | |
Unrealized Loss Position, Aggregate Losses | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (1) | |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 0 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | (1) | |
Asset-backed Securities | | |
Summary of cash equivalents and marketable securities: | | |
Available-for-sale Securities, Amortized Cost Basis | 489 | 453 |
Unrealized Gain | 0 | 0 |
Unrealized Loss | (1) | 0 |
Estimated Fair Value | 488 | 453 |
Classified as: | | |
Total cash equivalents and marketable securities | 488 | 453 |
Unrealized Loss Position, Fair Value | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value | 313 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value | 23 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 336 | |
Unrealized Loss Position, Aggregate Losses | | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (1) | |
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 0 | |
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss | (1) | |
Debt securities issued by United States Treasury | | |
Summary of cash equivalents and marketable securities: | | |
Available-for-sale Securities, Amortized Cost Basis | 385 | 534 |
Unrealized Gain | 0 | 3 |
Unrealized Loss | 0 | 0 |
Estimated Fair Value | 385 | 537 |
Classified as: | | |
Total cash equivalents and marketable securities | 385 | 537 |
Mortgage backed securities issued by United Sates government-sponsored enterprises | | |
Summary of cash equivalents and marketable securities: | | |
Available-for-sale Securities, Amortized Cost Basis | 261 | 274 |
Unrealized Gain | 4 | 5 |
Unrealized Loss | 0 | (1) |
Estimated Fair Value | 265 | 278 |
Classified as: | | |
Total cash equivalents and marketable securities | 265 | 278 |
Foreign government bonds | | |
Summary of cash equivalents and marketable securities: | | |
Available-for-sale Securities, Amortized Cost Basis | 75 | 85 |
Unrealized Gain | 0 | 0 |
Unrealized Loss | 0 | 0 |
Estimated Fair Value | 75 | 85 |
Classified as: | | |
Total cash equivalents and marketable securities | 75 | 85 |
Money market funds | | |
Summary of cash equivalents and marketable securities: | | |
Available-for-sale Securities, Amortized Cost Basis | 30 | 132 |
Unrealized Gain | 0 | 0 |
Unrealized Loss | 0 | 0 |
Estimated Fair Value | 30 | 132 |
Classified as: | | |
Total cash equivalents and marketable securities | $ 30 | $ 132 |