Investments (Schedule Of Other Investments) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Other Investment Not Readily Marketable [Line Items]
Other Investments	$ 5,277	$ 4,672
Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	5,277	4,672
Cost
Other Investment Not Readily Marketable [Line Items]
Other Investments	5,277	4,417
Other [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	234	168
Other [Member] | Other Accounting Method [Member] | Cost
Other Investment Not Readily Marketable [Line Items]
Other Investments	234	168
Partially-owned Investment Companies [Member] | Equity Method Investments [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	3,623	2,803
Partially-owned Investment Companies [Member] | Equity Method Investments [Member] | Cost
Other Investment Not Readily Marketable [Line Items]
Other Investments	3,623	2,803
Limited Partner [Member] | Cost-method Investments [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	538	549
Limited Partner [Member] | Cost-method Investments [Member] | Cost
Other Investment Not Readily Marketable [Line Items]
Other Investments	538	441
Investment Funds [Member] | Cost-method Investments [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	83	270
Investment Funds [Member] | Cost-method Investments [Member] | Cost
Other Investment Not Readily Marketable [Line Items]
Other Investments	83	123
Life Insurance Product Line [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	304	305
Life Insurance Product Line [Member] | Other Accounting Method [Member] | Cost
Other Investment Not Readily Marketable [Line Items]
Other Investments	304	305
Policy Loans [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	243	244
Policy Loans [Member] | Other Accounting Method [Member] | Cost
Other Investment Not Readily Marketable [Line Items]
Other Investments	243	244
Non-qualified separate account assets [Member] | Other Accounting Method [Member] | Fair Value
Other Investment Not Readily Marketable [Line Items]
Other Investments	252	333
Non-qualified separate account assets [Member] | Other Accounting Method [Member] | Cost
Other Investment Not Readily Marketable [Line Items]
Other Investments	$ 252	$ 333