Fair Value Measurements (Fair Value Hierarchy) (Details) - USD ($) $ in Millions | Jun. 30, 2015 | Dec. 31, 2014 |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | $ 5,205 | $ 5,004 |
Marketable available-for-sale equity securities | 15 | |
Deferred Compensation Plan Assets | 14 | 8 |
Deferred Compensation Plan Liabilities | 14 | 8 |
Notes payable | EMC | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Debt Instrument | 1,510 | 1,503 |
U.S. Government and agency obligations | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 655 | 542 |
U.S. and foreign corporate debt securities | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 3,292 | 3,234 |
Foreign governments and multi-national agency obligations | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 27 | 23 |
Municipal obligations | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 888 | 932 |
Asset-backed securities | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 36 | 53 |
Mortgage-backed securities | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 307 | 220 |
Fair Value, Measurements, Recurring | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 5,205 | 5,004 |
Foreign currency forward contracts, asset | | 1 |
Marketable available-for-sale equity securities | 15 | |
Foreign currency forward contracts, liability | (3) | (1) |
Fair Value, Measurements, Recurring | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 443 | 353 |
Foreign currency forward contracts, asset | | 0 |
Marketable available-for-sale equity securities | 15 | |
Foreign currency forward contracts, liability | 0 | 0 |
Fair Value, Measurements, Recurring | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 4,762 | 4,651 |
Foreign currency forward contracts, asset | | 1 |
Marketable available-for-sale equity securities | 0 | |
Foreign currency forward contracts, liability | (3) | (1) |
Fair Value, Measurements, Recurring | U.S. Government and agency obligations | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 655 | 542 |
Fair Value, Measurements, Recurring | U.S. Government and agency obligations | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 443 | 353 |
Fair Value, Measurements, Recurring | U.S. Government and agency obligations | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 212 | 189 |
Fair Value, Measurements, Recurring | U.S. and foreign corporate debt securities | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 3,292 | 3,234 |
Fair Value, Measurements, Recurring | U.S. and foreign corporate debt securities | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 0 | 0 |
Fair Value, Measurements, Recurring | U.S. and foreign corporate debt securities | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 3,292 | 3,234 |
Fair Value, Measurements, Recurring | Foreign governments and multi-national agency obligations | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 27 | 23 |
Fair Value, Measurements, Recurring | Foreign governments and multi-national agency obligations | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 0 | 0 |
Fair Value, Measurements, Recurring | Foreign governments and multi-national agency obligations | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 27 | 23 |
Fair Value, Measurements, Recurring | Municipal obligations | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 888 | 932 |
Fair Value, Measurements, Recurring | Municipal obligations | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 0 | 0 |
Fair Value, Measurements, Recurring | Municipal obligations | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 888 | 932 |
Fair Value, Measurements, Recurring | Asset-backed securities | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 36 | 53 |
Fair Value, Measurements, Recurring | Asset-backed securities | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 0 | 0 |
Fair Value, Measurements, Recurring | Asset-backed securities | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 36 | 53 |
Fair Value, Measurements, Recurring | Mortgage-backed securities | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 307 | 220 |
Fair Value, Measurements, Recurring | Mortgage-backed securities | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 0 | 0 |
Fair Value, Measurements, Recurring | Mortgage-backed securities | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Short-term investments: | 307 | 220 |
Money-market funds | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 990 | 1,130 |
Money-market funds | Fair Value, Measurements, Recurring | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 990 | 1,130 |
Money-market funds | Fair Value, Measurements, Recurring | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 990 | 1,130 |
Money-market funds | Fair Value, Measurements, Recurring | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 0 | 0 |
U.S. and foreign corporate debt securities | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 7 | 54 |
U.S. and foreign corporate debt securities | Fair Value, Measurements, Recurring | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 7 | 54 |
U.S. and foreign corporate debt securities | Fair Value, Measurements, Recurring | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 0 | 0 |
U.S. and foreign corporate debt securities | Fair Value, Measurements, Recurring | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 7 | 54 |
Municipal obligations | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 7 | |
Municipal obligations | Fair Value, Measurements, Recurring | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 7 | |
Municipal obligations | Fair Value, Measurements, Recurring | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 0 | |
Municipal obligations | Fair Value, Measurements, Recurring | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 7 | |
Foreign governments and multi-national agency obligations | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | | 2 |
Foreign governments and multi-national agency obligations | Fair Value, Measurements, Recurring | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | | 2 |
Foreign governments and multi-national agency obligations | Fair Value, Measurements, Recurring | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | | 0 |
Foreign governments and multi-national agency obligations | Fair Value, Measurements, Recurring | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | | 2 |
Total cash equivalents | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 1,004 | 1,186 |
Total cash equivalents | Fair Value, Measurements, Recurring | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 1,004 | 1,186 |
Total cash equivalents | Fair Value, Measurements, Recurring | Level 1 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | 990 | 1,130 |
Total cash equivalents | Fair Value, Measurements, Recurring | Level 2 | | |
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items] | | |
Cash equivalents: | $ 14 | $ 56 |