Investment securities - Equity securities and Other long-term investments (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Fixed income mutual funds
Equity securities and Other long-term investments
Fair value	$ 175.3	$ 157.7
Common stocks
Equity securities and Other long-term investments
Fair value	228.1	222.3
Other equity securities
Equity securities and Other long-term investments
Fair value	1.8	0.0
Equity securities
Equity securities and Other long-term investments
Cost or amortized cost	379.2	409.4
Gross unrealized gains	55.6	17.8
Gross unrealized losses	(37.3)	(50.8)
Net foreign currency gains	7.7	3.6
Fair value	405.2	380.0
Other long-term investments
Equity securities and Other long-term investments
Cost or amortized cost	315.4	337.6
Gross unrealized gains	49.9	32.6
Gross unrealized losses	(29.3)	(13.5)
Net foreign currency gains	10.8	8.3
Fair value	346.8	365.0
Other long-term investments \| Hedge funds and private equity funds
Equity securities and Other long-term investments
Fair value	269.0	301.4
Other long-term investments \| Limited liability companies and private equity securities
Equity securities and Other long-term investments
Fair value	$ 77.8	$ 63.6

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=120398452&loc=d3e534808-122878

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