|
Investments Measured at Fair Value on a Recurring Basis (Detail) (Fair Value, Measurements, Recurring [Member], USD $)
In Millions, unless otherwise specified
|
Sep. 30, 2014
|
Dec. 31, 2013
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
$ 1,470
|
$ 709
|
|
Marketable securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
1,367
|
580
|
|
Marketable securities | U.S. government and agency debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
337
|
354
|
|
Marketable securities | Mortgage and asset-backed debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
95
|
75
|
|
Marketable securities | Corporate debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
818
|
146
|
|
Marketable securities | Other debt and equity securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
117
|
5
|
|
Other Long-term Investments
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
103
|
129
|
|
Fair Value, Inputs, Level 1
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
356
|
372
|
|
Fair Value, Inputs, Level 1 | Marketable securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
337
|
353
|
|
Fair Value, Inputs, Level 1 | Marketable securities | U.S. government and agency debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
337
|
353
|
|
Fair Value, Inputs, Level 1 | Marketable securities | Mortgage and asset-backed debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
0
|
0
|
|
Fair Value, Inputs, Level 1 | Marketable securities | Corporate debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
0
|
0
|
|
Fair Value, Inputs, Level 1 | Marketable securities | Other debt and equity securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
0
|
0
|
|
Fair Value, Inputs, Level 1 | Other Long-term Investments
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
19
|
19
|
|
Fair Value, Inputs, Level 2
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
1,030
|
227
|
|
Fair Value, Inputs, Level 2 | Marketable securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
1,030
|
227
|
|
Fair Value, Inputs, Level 2 | Marketable securities | U.S. government and agency debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
0
|
1
|
|
Fair Value, Inputs, Level 2 | Marketable securities | Mortgage and asset-backed debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
95
|
75
|
|
Fair Value, Inputs, Level 2 | Marketable securities | Corporate debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
818
|
146
|
|
Fair Value, Inputs, Level 2 | Marketable securities | Other debt and equity securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
117
|
5
|
|
Fair Value, Inputs, Level 2 | Other Long-term Investments
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
0
|
0
|
|
Fair Value, Inputs, Level 3
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
84
|
110
|
|
Fair Value, Inputs, Level 3 | Marketable securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
0
|
0
|
|
Fair Value, Inputs, Level 3 | Marketable securities | U.S. government and agency debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
0
|
0
|
|
Fair Value, Inputs, Level 3 | Marketable securities | Mortgage and asset-backed debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
0
|
0
|
|
Fair Value, Inputs, Level 3 | Marketable securities | Corporate debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
0
|
0
|
|
Fair Value, Inputs, Level 3 | Marketable securities | Other debt and equity securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
0
|
0
|
|
Fair Value, Inputs, Level 3 | Other Long-term Investments
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
$ 84
|
$ 110
|