Investments (Schedule Of Other Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Other Investment Not Readily Marketable [Line Items]
Other Investments	$ 6,062	$ 5,277
Alternative Investment	4,921	4,244
Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	6,062	5,277
Alternative Investment	4,921	4,244
Other [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	234	234
Partially-owned Investment Companies [Member] | Equity Method Investments [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	4,142	3,623
Limited Partner [Member] | Cost-method Investments [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	508	538
Investment Funds [Member] | Cost-method Investments [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	271	83
Life Insurance Product Line [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	377	304
Policy Loans [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	247	243
Non-qualified separate account assets [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	$ 283	$ 252