Investments (Financing Receivables Past Due) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 7,320	$ 6,653
Financial Asset, Not Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	7,292	6,617
Financial Asset, 60 to 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 28	$ 36