Investments (Schedule Of Amortized Cost and Fair Value of Available-for-sale Securities) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 91,526	$ 90,493
Debt Securities, Available-for-sale, Allowance for Credit Loss	(27)	(14)	$ (15)	$ (20)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	910	3,220
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before tax	(2,930)	(591)
Available for sale, Fair Value	89,479	93,108
U.S. Treasury / Agency
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	2,111	2,111
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	31	109
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before tax	(40)	(6)
Available for sale, Fair Value	2,102	2,214
Non-U.S.
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	25,304	25,156
Debt Securities, Available-for-sale, Allowance for Credit Loss	(16)	(8)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	380	953
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before tax	(884)	(272)
Available for sale, Fair Value	24,784	25,829
Corporate and asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	38,469	37,844
Debt Securities, Available-for-sale, Allowance for Credit Loss	(11)	(6)
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	360	1,410
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before tax	(1,149)	(185)
Available for sale, Fair Value	37,669	39,063
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	20,511	20,080
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	90	532
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before tax	(796)	(123)
Available for sale, Fair Value	19,805	20,489
Municipal
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	5,131	5,302
Debt Securities, Available-for-sale, Allowance for Credit Loss	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	49	216
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before tax	(61)	(5)
Available for sale, Fair Value	$ 5,119	$ 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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Amortized cost of 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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