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Available-for-sale investments (Details Textual) (USD $)
In Millions, unless otherwise specified |
3 Months Ended | ||
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Mar. 31, 2013
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Mar. 31, 2012
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Dec. 31, 2012
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| Available-for-sale investments (Textual) [Abstract] | |||
| Cash | $ 433 | $ 370 | |
| Total realized gains | 85 | 67 | |
| Total realized losses | $ 18 | $ 19 | |
| X | ||||||||||
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- Details
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| X | ||||||||||
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- Definition
This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount 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. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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