Investment Securities (Schedule of Carrying Value of Investment Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Debt securities	$ 5,854.7	$ 6,011.8
Equity securities	0.0	47.2
Total investment securities	6,128.6	6,276.8
Non-marketable securities
Schedule Of Available For Sale And Held To Maturity Securities [Line Items]
Total investment securities	$ 273.9	$ 217.8

Schedule of available for sale and held to maturity securities.

No definition available.

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- Definition

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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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).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Sum of the carrying amounts as of the balance sheet date of all investments.

+ References

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-Name Accounting Standards Codification
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