INVESTMENTS - Carrying Value and Fair Value of HTM Debt Securities by Contractual Maturity Dates (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount;
Amortized cost, net	$ 248,274	$ 254,247
Held-to-maturity Securities, Debt Maturities, Fair Value;
Fair value	234,310	235,001
Allowance for credit losses on HTM debt securities	141	95
Mortgage-backed securities
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount;
Due within 1 year, amortized cost	13
After 1 but within 5 years, amortized cost	1,231
After 5 but within 10 years, amortized cost	785
After 10 years, amortized cost	73,567
Amortized cost, net	75,596	81,033
Held-to-maturity Securities, Debt Maturities, Fair Value;
Due within 1 year, fair value	13
After 1 but within 5 years, fair value	1,190
After 5 but within 10 years, fair value	750
After 10 years, fair value	66,435
Fair value	68,388	72,283
U.S. treasury securities
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount;
Due within 1 year, amortized cost	38,577
After 1 but within 5 years, amortized cost	92,773
After 5 but within 10 years, amortized cost	0
After 10 years, amortized cost	0
Amortized cost, net	131,350	131,776
Held-to-maturity Securities, Debt Maturities, Fair Value;
Due within 1 year, fair value	38,023
After 1 but within 5 years, fair value	86,956
After 5 but within 10 years, fair value	0
After 10 years, fair value	0
Fair value	124,979	121,868
State and municipal
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount;
Due within 1 year, amortized cost	33
After 1 but within 5 years, amortized cost	159
After 5 but within 10 years, amortized cost	1,724
After 10 years, amortized cost	7,042
Amortized cost, net	8,958	9,182
Held-to-maturity Securities, Debt Maturities, Fair Value;
Due within 1 year, fair value	33
After 1 but within 5 years, fair value	161
After 5 but within 10 years, fair value	1,666
After 10 years, fair value	6,708
Fair value	8,568	8,778
Foreign government
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount;
Due within 1 year, amortized cost	811
After 1 but within 5 years, amortized cost	695
After 5 but within 10 years, amortized cost	0
After 10 years, amortized cost	0
Amortized cost, net	1,506	2,210
Held-to-maturity Securities, Debt Maturities, Fair Value;
Due within 1 year, fair value	814
After 1 but within 5 years, fair value	696
After 5 but within 10 years, fair value	0
After 10 years, fair value	0
Fair value	1,510	$ 2,152
All other
Held-to-maturity Securities, Debt Maturities, Net Carrying Amount;
Due within 1 year, amortized cost	0
After 1 but within 5 years, amortized cost	0
After 5 but within 10 years, amortized cost	10,779
After 10 years, amortized cost	20,085
Amortized cost, net	30,864
Held-to-maturity Securities, Debt Maturities, Fair Value;
Due within 1 year, fair value	0
After 1 but within 5 years, fair value	0
After 5 but within 10 years, fair value	10,788
After 10 years, fair value	20,077
Fair value	$ 30,865

Amount, excluding accrued interest, of allowance for credit loss on investment in debt security measured at amortized cost (held-to-maturity).

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