Basis of Presentation and Significant Accounting Policies Additional Information (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Derivative [Line Items]
Stockholders' Equity Attributable to Noncontrolling Interest	$ 60	$ 60
Preferred Stock, Shares Issued	0
Fixed Income Securities [Member]
Derivative [Line Items]
Accrued Investment Income Receivable	$ 10

Interest, dividends, rents, ancillary and other revenues earned but not yet received by the entity on its investments.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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