Investments (Components of Net Investment Gains (Losses) - Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Gain (Loss) on Securities [Line Items]
Net investment gains (losses)	$ (67)	$ 12
Foreign Exchange
Gain (Loss) on Securities [Line Items]
Net investment gains (losses)	$ (15)	$ 0

Amount of realized gain (loss) on investment.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-04.3(a))
-URI https://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263

Name:	us-gaap_RealizedInvestmentGainsLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration