Investments (Schedule Of Amortized Cost and Fair Value of Available-for-Sale Securities) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	$ 93,355	$ 90,493
Debt Securities, Available-for-sale, Allowance for Credit Loss	(169)	(14)	$ (20)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	174	3,220
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(8,140)	(591)
Available for sale, Fair Value	85,220	93,108
U.S. Treasury / Agency
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	2,792	2,111
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	5	109
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(171)	(6)
Available for sale, Fair Value	2,626	2,214
Non-U.S.
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	28,064	25,156
Debt Securities, Available-for-sale, Allowance for Credit Loss	(59)	(8)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	108	953
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(2,205)	(272)
Available for sale, Fair Value	25,908	25,829
Corporate and asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	40,547	37,844
Debt Securities, Available-for-sale, Allowance for Credit Loss	(107)	(6)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	49	1,410
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(3,534)	(185)
Available for sale, Fair Value	36,955	39,063
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	17,871	20,080
Debt Securities, Available-for-sale, Allowance for Credit Loss	(3)	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	4	532
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(2,021)	(123)
Available for sale, Fair Value	15,851	20,489
Municipal
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-Sale, Amortized Cost	4,081	5,302
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	8	216
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	(209)	(5)
Available for sale, Fair Value	$ 3,880	$ 5,513

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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