Securities Sold Under Agreements to Repurchase (Repurchase Agreements Accounted for as Secured Borrowings) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	$ 561.4	$ 531.9
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	561.4	531.9
Amounts related to agreements not included in Note 23	0.0	0.0
U.S. Treasury and Agency Securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	561.4	531.9
OVERNIGHT AND CONTINUOUS
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	561.4	32.4
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	561.4	32.4
Amounts related to agreements not included in Note 23	0.0	0.0
OVERNIGHT AND CONTINUOUS \| U.S. Treasury and Agency Securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	561.4	32.4
UP TO 30 DAYS
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	0.0	499.5
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest	0.0	499.5
Amounts related to agreements not included in Note 23	0.0	0.0
UP TO 30 DAYS \| U.S. Treasury and Agency Securities
Transfer of Certain Financial Assets Accounted for as Secured Borrowings [Line Items]
Borrowings	$ 0.0	$ 499.5

Additional cash collateral deposited with derivative counterparties not offset against derivative liabilities on the consolidated balance sheet as amounts exceed the net derivative positions with the counterparties.

No definition available.

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- Definition

Amount excluding accrued interest, of allowance for credit loss on 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
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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- Definition

Carrying value, as of the balance sheet date, of securities sold under agreements to repurchase where the transferor maintains effective control over the assets, accounting for them as secured debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 7
-URI https://asc.fasb.org/extlink&oid=109249958&loc=SL34722452-111729

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- Definition

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.

+ References

No definition available.

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