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

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).

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