Investment securities - Equity securities and Other long-term investments (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Equity securities
Equity securities and Other long-term investments
Cost or amortized cost	$ 409.5	$ 379.2
Gross unrealized gains	37.4	55.6
Gross unrealized losses	(98.4)	(37.3)
Net foreign currency gains	18.1	7.7
Fair value	366.6	405.2
Other long-term investments
Equity securities and Other long-term investments
Cost or amortized cost	323.2	315.4
Gross unrealized gains	50.3	49.9
Gross unrealized losses	(31.7)	(29.3)
Net foreign currency gains	13.7	10.8
Fair value	355.5	346.8
Other long-term investments \| Hedge funds and private equity funds
Equity securities and Other long-term investments
Fair value	279.6	269.0
Other long-term investments \| Limited liability companies and private equity securities
Equity securities and Other long-term investments
Fair value	75.9	77.8
Fixed income mutual funds
Equity securities and Other long-term investments
Fair value	192.1	175.3
Common shares
Equity securities and Other long-term investments
Fair value	184.4	228.1
Other equity securities
Equity securities and Other long-term investments
Fair value	$ (9.9)	$ 1.8

Amount of unrealized gain on investment in debt and equity securities.

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Amount of unrealized loss on investment in debt and equity securities.

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The amount of net foreign currency gains (losses) on investment securities measured at fair value.

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- Definition

Cost of investment in debt investment in debt security measured at fair value with change in fair value recognized in net income (trading) and investment in equity security 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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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.4)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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