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Investments AFS (Details) (USD $)
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Sep. 30, 2014
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Mar. 31, 2014
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| Investments [Abstract] | ||
| Amount of short-term investments | $ 801,670,000 | $ 878,182,000 |
| Amount of long-term investments | 841,277,000 | 798,712,000 |
| Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value | 833,300,000 | |
| Amount of corporate debt securities with no contractual maturity excluded from estimated fair value of available-for-sale securities | $ 6,200,000 |
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- Definition
This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of available-for-sale debt securities at fair value that do not have a single maturity date and which the entity has decided to disclose separately rather than allocating the fair value over several maturity groupings. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition
The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Investments which are intended to be sold in the short term (usually less than one year or the normal operating cycle, whichever is longer) including trading securities, available-for-sale securities, held-to-maturity securities, and other short-term investments not otherwise listed in the existing taxonomy. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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