INVESTMENTS - Fair Value of AFS Debt Securities by Contractual Maturity Date (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Available for Sale Securities, Debt Maturities, Amortized Cost
Amortized cost	$ 255,608	$ 289,363
Available for Sale Securities, Debt Maturities, Fair Value
Total fair value	$ 249,679	$ 288,522
Available for Sale Securities, Debt Maturities, Weighted Average Yield
Total	3.34%	1.94%
Mortgage-backed securities
Available for Sale Securities, Debt Maturities, Amortized Cost
Due within 1 year, amortized cost	$ 42	$ 188
After 1 but within 5 years, amortized cost	523	211
After 5 but within 10 years, amortized cost	468	523
After 10 years, amortized cost	11,466	32,547
Amortized cost	12,499	33,469
Available for Sale Securities, Debt Maturities, Fair Value
Due within 1 year, fair value	44	189
After 1 but within 5 years, fair value	513	211
After 5 but within 10 years, fair value	440	559
After 10 Years, fair value	10,752	32,662
Total fair value	$ 11,749	$ 33,621
Available for Sale Securities, Debt Maturities, Weighted Average Yield
Due within 1 year, weighted average yield	2.02%	0.79%
After 1 but within 5 years, weighted average yield	2.31%	1.07%
After 5 but within 10 years, weighted average yield	3.46%	3.41%
After 10 Years, weighted average yield	3.46%	2.73%
Total	3.41%	2.72%
U.S. Treasury and federal agency securities
Available for Sale Securities, Debt Maturities, Amortized Cost
Due within 1 year, amortized cost	$ 25,935	$ 34,321
After 1 but within 5 years, amortized cost	68,455	87,987
After 5 but within 10 years, amortized cost	342	361
After 10 years, amortized cost	0	0
Amortized cost	94,732	122,669
Available for Sale Securities, Debt Maturities, Fair Value
Due within 1 year, fair value	25,829	34,448
After 1 but within 5 years, fair value	66,166	87,633
After 5 but within 10 years, fair value	295	359
After 10 Years, fair value	0	0
Total fair value	$ 92,290	$ 122,440
Available for Sale Securities, Debt Maturities, Weighted Average Yield
Due within 1 year, weighted average yield	2.81%	1.05%
After 1 but within 5 years, weighted average yield	1.17%	0.81%
After 5 but within 10 years, weighted average yield	2.53%	1.42%
After 10 Years, weighted average yield	0.00%	0.00%
Total	1.62%	0.87%
State and municipal
Available for Sale Securities, Debt Maturities, Amortized Cost
Due within 1 year, amortized cost	$ 19	$ 40
After 1 but within 5 years, amortized cost	94	121
After 5 but within 10 years, amortized cost	305	156
After 10 years, amortized cost	1,945	2,326
Amortized cost	2,363	2,643
Available for Sale Securities, Debt Maturities, Fair Value
Due within 1 year, fair value	18	40
After 1 but within 5 years, fair value	92	124
After 5 but within 10 years, fair value	302	161
After 10 Years, fair value	1,811	2,296
Total fair value	$ 2,223	$ 2,621
Available for Sale Securities, Debt Maturities, Weighted Average Yield
Due within 1 year, weighted average yield	1.79%	2.09%
After 1 but within 5 years, weighted average yield	3.07%	3.16%
After 5 but within 10 years, weighted average yield	3.55%	3.18%
After 10 Years, weighted average yield	3.51%	3.15%
Total	3.49%	3.14%
Foreign government
Available for Sale Securities, Debt Maturities, Amortized Cost
Due within 1 year, amortized cost	$ 64,795	$ 49,263
After 1 but within 5 years, amortized cost	67,935	64,555
After 5 but within 10 years, amortized cost	2,491	3,736
After 10 years, amortized cost	427	1,872
Amortized cost	135,648	119,426
Available for Sale Securities, Debt Maturities, Fair Value
Due within 1 year, fair value	64,479	49,223
After 1 but within 5 years, fair value	66,150	63,961
After 5 but within 10 years, fair value	2,250	3,656
After 10 Years, fair value	398	1,900
Total fair value	$ 133,277	$ 118,740
Available for Sale Securities, Debt Maturities, Weighted Average Yield
Due within 1 year, weighted average yield	4.25%	2.53%
After 1 but within 5 years, weighted average yield	4.80%	3.14%
After 5 but within 10 years, weighted average yield	2.86%	1.72%
After 10 Years, weighted average yield	3.80%	1.52%
Total	4.50%	2.82%
All other
Available for Sale Securities, Debt Maturities, Amortized Cost
Due within 1 year, amortized cost	$ 4,452	$ 5,175
After 1 but within 5 years, amortized cost	5,162	5,177
After 5 but within 10 years, amortized cost	695	750
After 10 years, amortized cost	57	54
Amortized cost	10,366	11,156
Available for Sale Securities, Debt Maturities, Fair Value
Due within 1 year, fair value	4,441	5,180
After 1 but within 5 years, fair value	4,988	5,149
After 5 but within 10 years, fair value	693	750
After 10 Years, fair value	18	21
Total fair value	$ 10,140	$ 11,100
Available for Sale Securities, Debt Maturities, Weighted Average Yield
Due within 1 year, weighted average yield	1.52%	0.94%
After 1 but within 5 years, weighted average yield	4.82%	1.91%
After 5 but within 10 years, weighted average yield	11.35%	2.08%
After 10 Years, weighted average yield	3.81%	4.28%
Total	3.83%	1.48%