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Investments (Schedule Of Amortized Cost and Fair Value of Available-for-Sale Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 93,316		$ 90,493
Debt Securities, Available-for-sale, Allowance for Credit Loss	(147)	$ (78)	(14)	$ (12)	$ (11)	$ (20)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	119		3,220
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before tax	(9,547)		(591)
Available for sale, Fair Value	83,741		93,108
U.S. Treasury / Agency
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	2,725		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	(174)		(6)
Available for sale, Fair Value	2,556		2,214
Non-U.S.
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	26,766		25,156
Debt Securities, Available-for-sale, Allowance for Credit Loss	(61)		(8)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	77		953
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before tax	(2,599)		(272)
Available for sale, Fair Value	24,183		25,829
Corporate and asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	40,776		37,844
Debt Securities, Available-for-sale, Allowance for Credit Loss	(85)		(6)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	30		1,410
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before tax	(4,341)		(185)
Available for sale, Fair Value	36,380		39,063
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	18,425		20,080
Debt Securities, Available-for-sale, Allowance for Credit Loss	(1)		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1		532
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before tax	(2,190)		(123)
Available for sale, Fair Value	16,235		20,489
Municipal
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	4,624		5,302
Debt Securities, Available-for-sale, Allowance for Credit Loss	0		0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	6		216
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before tax	(243)		(5)
Available for sale, Fair Value	$ 4,387		$ 5,513