Financing Agreements - Financing Agreements, at Fair Values Narrative (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Dec. 31, 2021
Financing Agreement
Financing Agreements [Line Items]
Cash pledged as collateral	$ 13.2	$ 10.2
Non Mark to Market Financing Facilities
Financing Agreements [Line Items]
Financial instruments	$ 511.6
Minimum \| Non Mark to Market Financing Facilities
Financing Agreements [Line Items]
Facility maturity period	3 months
Extension term	13 months
Maximum \| Non Mark to Market Financing Facilities
Financing Agreements [Line Items]
Facility maturity period	42 months
Extension term	39 months

Amount of right to receive cash collateral under master netting arrangements that have not been offset against securities sold under agreement to repurchase.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 13
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226016-175313

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226038-175313

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (d)(2)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Name:	us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseCollateralRightToReclaimCash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant