|
Investments Measured at Fair Value on a Recurring Basis (Detail) (Fair Value, Measurements, Recurring, USD $)
In Millions
|
Jun. 30, 2011
|
Dec. 31, 2010
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
$ 1,204
|
$ 1,150
|
|
Fair Value, Inputs, Level 1
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
188
|
247
|
|
Fair Value, Inputs, Level 1 | Marketable securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
170
|
247
|
|
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 |
165
|
206
|
|
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 |
5
|
41
|
|
Fair Value, Inputs, Level 1 | Other Long-term Investments
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
18
|
|
|
Fair Value, Inputs, Level 2
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
776
|
498
|
|
Fair Value, Inputs, Level 2 | Marketable securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
776
|
498
|
|
Fair Value, Inputs, Level 2 | Marketable securities | Asset-backed Securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
230
|
222
|
|
Fair Value, Inputs, Level 2 | Marketable securities | Corporate debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
471
|
183
|
|
Fair Value, Inputs, Level 2 | Marketable securities | U.S. state and local municipal debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
17
|
33
|
|
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 |
58
|
60
|
|
Fair Value, Inputs, Level 3
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
240
|
405
|
|
Fair Value, Inputs, Level 3 | Marketable securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
|
138
|
|
Fair Value, Inputs, Level 3 | Marketable securities | Asset-backed Securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
|
79
|
|
Fair Value, Inputs, Level 3 | Marketable securities | U.S. state and local municipal debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
|
45
|
|
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 |
|
14
|
|
Fair Value, Inputs, Level 3 | Other Long-term Investments
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
240
|
267
|
|
Marketable securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
946
|
883
|
|
Marketable securities | U.S. government and agency debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
165
|
206
|
|
Marketable securities | Asset-backed Securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
230
|
301
|
|
Marketable securities | Corporate debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
471
|
183
|
|
Marketable securities | U.S. state and local municipal debt securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
17
|
78
|
|
Marketable securities | Other debt and equity securities
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
63
|
115
|
|
Other Long-term Investments
|
|
|
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |
|
|
| Investments |
$ 258
|
$ 267
|