Investments (Schedule Of Available-For-Sale Securities Whose Value Is Below Amortized Cost) (Details) $ in Millions	Jun. 30, 2023 USD ($) security	Dec. 31, 2022 USD ($) security
Schedule of Available-for-sale Securities [Line Items]
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 27,262	$ 71,770
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	55,728	11,352
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	82,990	83,122
Less Than or Equal to Twelve Months	1,505	10,425
Greater Than Twelve Months	10,135	2,593
Continuous Unrealized Loss Position, Total	$ 11,640	$ 13,018
Number of Securities - Total | security	8,331	8,175
Fair Value Decline, Greater Than 20% [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less than six months	$ 4,669	$ 11,351
Fair Value - Six months or greater, but less than nine months	208	4,411
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months	4,214	447
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer	4,687	2
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	13,778	16,211
Gross Unrealized Losses - Less than six months	1,324	3,659
Gross Unrealized Losses - Six months or greater, but less than nine months	85	2,226
Less Than or Equal to Twelve Months	1,588	302
Greater Than Twelve Months	2,355	1
Continuous Unrealized Loss Position, Total	$ 5,352	$ 6,188
Number of Securities - Less than six months | security	674	1,500
Number of Securities - Six months or greater, but less than nine months | security	34	650
Number of Securities - Nine months or greater, but less than twelve months | security	697	74
Number of Securities - Twelve months or greater | security	666	15
Number of Securities - Total | security	2,071	2,239