Fair Value (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2023	Dec. 31, 2022
Fair Value Disclosure [Line Items]
Transfers between Fair Value Hierarchies	$ 0.0	$ 0.0
Allowance for Credit Loss	0.8	0.9
U.S. Treasury debt securities
Fair Value Disclosure [Line Items]
Allowance for Credit Loss	0.0	0.0
Available-for-sale Securities, Maturities, Next Twelve Months, Fair Value	6.3
Corporate/Other debt securities
Fair Value Disclosure [Line Items]
Allowance for Credit Loss	0.8	$ 0.9
Available-for-sale Securities, Maturities, Next Twelve Months, Fair Value	$ 4.1

Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 320
-Section 50
-Paragraph 3A
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126980459&loc=SL120269850-112803

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27198-111563

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

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