Investments (Schedule Of Other Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Other Investment Not Readily Marketable [Line Items]
Other Investments	$ 7,945	$ 6,062
Alternative Investment	6,770	4,921
Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	7,945	6,062
Alternative Investment	6,770	4,921
Other [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	188	234
Partially-owned Investment Companies [Member] | Equity Method Investments [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	5,969	4,142
Limited Partner [Member] | Cost-method Investments [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	547	508
Investment Funds [Member] | Cost-method Investments [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	254	271
Life Insurance Product Line [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	438	377
Policy Loans [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	233	247
Non-qualified separate account assets [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	$ 316	$ 283