Assets And Liabilities Measured At Fair Value (Assets And Liabilities Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions |
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Cash equivalents | $ 655 | $ 625 |
| Available-for-sale securities | 2,275 | 1,846 |
| Investments in and Advances to Affiliates, at Fair Value | 3,635 | 3,161 |
| Debt | 1,846 | 1,667 |
| Level 1 | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Cash equivalents | 655 | 625 |
| Available-for-sale securities | 2,275 | 1,846 |
| Investments in and Advances to Affiliates, at Fair Value | 3,635 | 3,161 |
| Significant Other Observable Inputs (Level 2) | ||
| Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ||
| Debt | $ 1,846 | $ 1,667 |
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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. No definition available.
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- Definition Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available.
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- Definition Value of the investment at close of period. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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