Variable Interest Entities (Consolidated Variable Interest Entity Asset And Liability Information) (Details) - Total Return Swap [Member] - Derivative Instruments Not Designated and Not Qualifying as Hedging Instruments [Member] $ in Millions	Sep. 30, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Disclosure Of Variable Interest Entities Assets And Liabilities [Line Items]
Number of Instruments, Assets | security	1	1
Notional Amounts, Assets	$ 543	$ 568
Carrying Value, Assets