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Financial Instruments (Details 1) - USD ($) $ in Millions | Dec. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Marketable Debt and Equity Securities |  |
Debt securities, amortized cost | $ 2,965.0 | $ 3,694.0
Debt securities, gross unrealized gains | 6.0 | 1.3
Debt securities, gross unrealized losses | 0.7 | 6.0
Debt securities, fair value | 2,970.3 | 3,689.3
Corporate debt securities Current |  |
Marketable Debt and Equity Securities |  |
Debt securities, amortized cost | 1,057.2 | 1,608.4
Debt securities, gross unrealized gains | 1.0 | 0.0
Debt securities, gross unrealized losses | 0.0 | 0.9
Debt securities, fair value | 1,058.2 | 1,607.5
Corporate debt securities Non-current |  |
Marketable Debt and Equity Securities |  |
Debt securities, amortized cost | 633.9 | 854.9
Debt securities, gross unrealized gains | 3.0 | 0.7
Debt securities, gross unrealized losses | 0.0 | 3.9
Debt securities, fair value | 636.9 | 851.7
Government securities Current |  |
Marketable Debt and Equity Securities |  |
Debt securities, amortized cost | 502.9 | 706.1
Debt securities, gross unrealized gains | 0.4 | 0.1
Debt securities, gross unrealized losses | 0.0 | 0.4
Debt securities, fair value | 503.3 | 705.8
Government securities Non-current |  |
Marketable Debt and Equity Securities |  |
Debt securities, amortized cost | 510.1 | 264.0
Debt securities, gross unrealized gains | 0.8 | 0.1
Debt securities, gross unrealized losses | 0.3 | 0.3
Debt securities, fair value | 510.6 | 263.8
Mortgage and other asset backed securities Current |  |
Marketable Debt and Equity Securities |  |
Debt securities, amortized cost | 0.7 | 0.1
Debt securities, gross unrealized gains | 0.0 | 0.0
Debt securities, gross unrealized losses | 0.0 | 0.0
Debt securities, fair value | 0.7 | 0.1
Mortgage and other asset backed securities Non-current |  |
Marketable Debt and Equity Securities |  |
Debt securities, amortized cost | 260.2 | 260.5
Debt securities, gross unrealized gains | 0.8 | 0.4
Debt securities, gross unrealized losses | 0.4 | 0.5
Debt securities, fair value | 260.6 | 260.4
Marketable equity securities |  |
Marketable Debt and Equity Securities |  |
Marketable equity securities, amortized cost | 218.4 | 496.2
Marketable equity securities, gross unrealized gains | 132.1 | 127.7
Marketable equity securities, gross unrealized losses | 13.0 | 8.5
Marketable equity securities, fair value | $ 337.5 | $ 615.4

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- Definition Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 + Details
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- Definition Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27161-111563 + Details
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