Pledged and Restricted Assets - Accepted Collateral (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Reverse repurchase agreements
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Fair value of securities received as collateral that can be resold or repledged	$ 1,179.8	$ 707.8
Fair value of accepted collateral	500.0	0.0
Derivative contracts
Customer Securities for which Entity has Right to Sell or Repledge (Including Securities Sold or Repledged) [Line Items]
Fair value of securities received as collateral that can be resold or repledged	$ 0.9	$ 16.8

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

Fair value of collateral permitted, by contact or custom, to be sold or re-pledged.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

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- Definition

The carrying amount (fair value) as of the balance sheet date of securities held that had been pledged by counterparties under financing and lending arrangements, pursuant to which the entity has the right by agreement or custom to sell or re-pledge such securities.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121611835&loc=d3e5086-111524

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