Investments - Investments - Concentration of Credit Risk (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Investments, All Other Investments [Abstract]
Fair Value, Concentration of Risk, Investments	$ 0	$ 0

This item represents disclosure of all significant concentrations of credit risk or market risk arising from the subject financial instrument (as defined), whether from an individual counterparty or groups of counterparties.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13531-108611

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