Financial Instruments (Details 1) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Amortized cost	$ 2,223.6	$ 2,049.1
Gross unrealized gains	1.4	2.3
Gross unrealized losses	(1.1)	(0.4)
Fair value	2,223.9	2,051.0
Marketable equity securities, fair value	2,223.9	2,051.0
Equity Securities, FV-NI, Cost		1,239.5
Equity Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax		749.7
Equity Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, Before Tax		(14.9)
Equity Securities, FV-NI		1,974.3
Corporate debt securities Current
Debt Securities, Available-for-sale [Line Items]
Amortized cost	1,072.2	897.8
Gross unrealized gains	0.3	0.4
Gross unrealized losses	(0.4)	(0.2)
Fair value	1,072.1	898.0
Corporate debt securities Non-current
Debt Securities, Available-for-sale [Line Items]
Amortized cost	309.9	402.5
Gross unrealized gains	0.6	1.1
Gross unrealized losses	(0.1)	(0.1)
Fair value	310.4	403.5
Government securities Current
Debt Securities, Available-for-sale [Line Items]
Amortized cost	236.5	380.6
Gross unrealized gains	0.1	0.1
Gross unrealized losses	0.0	0.0
Fair value	236.6	380.7
Government securities Non-current
Debt Securities, Available-for-sale [Line Items]
Amortized cost	452.1	245.9
Gross unrealized gains	0.2	0.5
Gross unrealized losses	(0.3)	0.0
Fair value	452.0	246.4
Mortgage and other asset backed securities Current
Debt Securities, Available-for-sale [Line Items]
Amortized cost	0.2	0.2
Gross unrealized gains	0.0	0.0
Gross unrealized losses	0.0	0.0
Fair value	0.2	0.2
Mortgage and other asset backed securities Non-current
Debt Securities, Available-for-sale [Line Items]
Amortized cost	152.7	122.1
Gross unrealized gains	0.2	0.2
Gross unrealized losses	(0.3)	(0.1)
Fair value	152.6	122.2
Equity Securities, Current
Debt Securities, Available-for-sale [Line Items]
Equity Securities, FV-NI, Cost	1,168.9	70.6
Equity Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	607.6	15.9
Equity Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, Before Tax	(183.0)	0.0
Equity Securities, FV-NI	1,593.5	86.5
Equity Securities, Non-Current
Debt Securities, Available-for-sale [Line Items]
Equity Securities, FV-NI, Cost	1,168.9	1,168.9
Equity Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	607.6	733.8
Equity Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, Before Tax	(183.0)	(14.9)
Equity Securities, FV-NI	$ 1,593.5	$ 1,887.8

Equity Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax

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Equity Securities, Available-for-Sale, Accumulated Gross Unrealized Loss, Before Tax

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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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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).

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Amortized cost of 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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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Cost of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Excludes equity method investment and investment in equity security without readily determinable fair value.

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