Investment securities - Net investment income (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net Investment Income
Total investment income	$ 28.2	$ 22.6	$ 52.0	$ 35.7
Investment expenses	(3.8)	(3.4)	(7.5)	(5.7)
Net investment income	24.4	19.2	44.5	30.0
Fixed maturity investments
Net Investment Income
Total investment income	13.1	13.7	27.2	23.6
Short-term investments
Net Investment Income
Total investment income	4.8	0.5	7.9	1.3
Equity securities
Net Investment Income
Total investment income	7.1	7.1	9.8	8.3
Other long-term investments
Net Investment Income
Total investment income	$ 3.2	$ 1.3	$ 7.1	$ 2.5

Amount, before investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

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-SubTopic 220
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Amount of expenses related to the generation of investment income.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments.

+ References

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