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

Amount of debt securities categorized neither as held-to-maturity nor trading.

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