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INVESTMENTS - Debt Securities Held-to-Maturity (Details) - USD ($) $ in Millions	1 Months Ended
	Jan. 31, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Held-to-maturity debt securities
Amortized cost, net		$ 262,066		$ 268,863
Gross unrealized gains		41		101
Gross unrealized losses		24,086		25,316
Fair value		238,021		243,648
Allowance for credit losses on HTM debt securities		99	$ 104	120	$ 105	$ 85	$ 87
Transfer of securities from HTM to AFS, unrealized gain	$ 100
Fair value		238,021		243,648
Mortgage-backed securities - U.S. government-sponsored agency guaranteed
Held-to-maturity debt securities
Amortized cost, net		83,541		90,063
Gross unrealized gains		6		58
Gross unrealized losses		9,708		10,033
Fair value		73,839		80,088
Fair value		73,839		80,088
Mortgage-backed securities - Non-U.S. residential
Held-to-maturity debt securities
Amortized cost, net		362		445
Gross unrealized gains		0		0
Gross unrealized losses		0		0
Fair value		362		445
Fair value		362		445
Commercial
Held-to-maturity debt securities
Amortized cost, net		1,145		1,114
Gross unrealized gains		0		5
Gross unrealized losses		149		1
Fair value		996		1,118
Fair value		996		1,118
Mortgage-backed securities
Held-to-maturity debt securities
Amortized cost, net		85,048		91,622
Gross unrealized gains		6		63
Gross unrealized losses		9,857		10,034
Fair value		75,197		81,651
Fair value		75,197		81,651
U.S. treasury securities
Held-to-maturity debt securities
Amortized cost, net		134,944		134,961
Gross unrealized gains		0		0
Gross unrealized losses		13,091		13,722
Fair value		121,853		121,239
Fair value		121,853		121,239
State and municipal
Held-to-maturity debt securities
Amortized cost, net		9,181		9,237
Gross unrealized gains		35		34
Gross unrealized losses		628		764
Fair value		8,588		8,507
Fair value		8,588		8,507
Foreign government
Held-to-maturity debt securities
Amortized cost, net		2,360		2,075
Gross unrealized gains		0		0
Gross unrealized losses		93		93
Fair value		2,267		1,982
Fair value		2,267		1,982
Asset-backed securities
Held-to-maturity debt securities
Amortized cost, net		30,533		30,968
Gross unrealized gains		0		4
Gross unrealized losses		417		703
Fair value		30,116		30,269
Fair value		$ 30,116		$ 30,269