INVESTMENTS - Fair Value of AFS Debt Securities by Contractual Maturity Date (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Fair value
Total fair value	$ 240,487	$ 249,679
Mortgage-backed securities
Amoritzed cost
Amortized cost, due within 1 year	6	42
Amortized cost, after 1 but within 5 years	406	523
Amortized cost, after 5 but within 10 years	478	468
Amortized cost, after 10 years	14,648	11,466
Amortized cost	15,538	12,499
Fair value
Fair value, due within 1 year	6	44
Fair value, after 1 but within 5 years	396	513
Fair value, after 5 but within 10 years	456	440
Fair value, after 10 years	14,100	10,752
Total fair value	14,958	11,749
U.S. Treasury and federal agency securities
Amoritzed cost
Amortized cost, due within 1 year	23,045	25,935
Amortized cost, after 1 but within 5 years	65,283	68,455
Amortized cost, after 5 but within 10 years	393	342
Amortized cost, after 10 years	0	0
Amortized cost	88,721	94,732
Fair value
Fair value, due within 1 year	22,947	25,829
Fair value, after 1 but within 5 years	63,378	66,166
Fair value, after 5 but within 10 years	352	295
Fair value, after 10 years	0	0
Total fair value	86,677	92,290
State and municipal
Amoritzed cost
Amortized cost, due within 1 year	17	19
Amortized cost, after 1 but within 5 years	96	94
Amortized cost, after 5 but within 10 years	316	305
Amortized cost, after 10 years	1,965	1,945
Amortized cost	2,394	2,363
Fair value
Fair value, due within 1 year	18	18
Fair value, after 1 but within 5 years	94	92
Fair value, after 5 but within 10 years	313	302
Fair value, after 10 years	1,868	1,811
Total fair value	2,293	2,223
Foreign government
Amoritzed cost
Amortized cost, due within 1 year	58,340	64,795
Amortized cost, after 1 but within 5 years	65,203	67,935
Amortized cost, after 5 but within 10 years	2,990	2,491
Amortized cost, after 10 years	463	427
Amortized cost	126,996	135,648
Fair value
Fair value, due within 1 year	58,073	64,479
Fair value, after 1 but within 5 years	63,774	66,150
Fair value, after 5 but within 10 years	2,804	2,250
Fair value, after 10 years	433	398
Total fair value	125,084	133,277
All other
Amoritzed cost
Amortized cost, due within 1 year	5,192	4,452
Amortized cost, after 1 but within 5 years	5,713	5,162
Amortized cost, after 5 but within 10 years	719	695
Amortized cost, after 10 years	67	57
Amortized cost	11,691	10,366
Fair value
Fair value, due within 1 year	5,178	4,441
Fair value, after 1 but within 5 years	5,545	4,988
Fair value, after 5 but within 10 years	717	693
Fair value, after 10 years	35	18
Total fair value	11,475	10,140
Debt securities AFS
Amoritzed cost
Amortized cost	245,340	255,608
Fair value
Total fair value	$ 240,487	$ 249,679

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