FAIR VALUE MEASUREMENTS - Instruments Not Carried At Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financial liabilities:
Securities sold under agreements to repurchase	$ 1,413,068	$ 833,568
Insurance
Financial assets:
Cash and cash equivalents	11,954,675	6,118,231	$ 3,391,934	$ 0
Restricted cash and cash equivalents	342,954	308,383	$ 300,404	$ 0
Financial liabilities:
Funds withheld payable at interest	1,423,242	1,059,820
Securities sold under agreements to repurchase	1,358,434	805,316
Insurance | Level III
Financial assets:
Funds withheld receivables at interest	88,661
Financial liabilities:
Policy liabilities - policyholder account balances	1,474,970
Funds withheld payable at interest	(2,447,303)
Insurance | Carrying Value
Financial assets:
Mortgage and other loan receivables	38,480,525	34,303,183
Policy loans	1,556,030	868,911
FHLB common stock and other investments	173,148	163,289
Funds withheld receivables at interest	2,624,984	2,855,251
Cash and cash equivalents	11,954,675	6,118,231
Restricted cash and cash equivalents	342,954	308,383
Total financial assets	55,132,316	44,617,248
Financial liabilities:
Policy liabilities - policyholder account balances	53,821,432	48,403,949
Funds withheld payable at interest	36,786,825	26,227,183
Debt obligations	2,587,857	2,128,166
Securities sold under agreements to repurchase	1,358,434	805,316
Total financial liabilities	94,554,548	77,564,614
Insurance | Fair Value
Financial assets:
Mortgage and other loan receivables	35,539,059	31,256,107
Policy loans	1,341,005	789,726
FHLB common stock and other investments	173,148	163,289
Funds withheld receivables at interest	2,624,984	2,855,251
Cash and cash equivalents	11,954,675	6,118,231
Restricted cash and cash equivalents	342,954	308,383
Total financial assets	51,975,825	41,490,987
Financial liabilities:
Policy liabilities - policyholder account balances	52,362,414	45,711,562
Funds withheld payable at interest	36,786,825	26,227,183
Debt obligations	2,396,587	1,698,526
Securities sold under agreements to repurchase	1,358,434	805,316
Total financial liabilities	92,904,260	74,442,587
Insurance | Fair Value | Level I
Financial assets:
Mortgage and other loan receivables	0	0
Policy loans	0	0
FHLB common stock and other investments	0	0
Funds withheld receivables at interest	0	0
Cash and cash equivalents	11,954,675	6,118,231
Restricted cash and cash equivalents	342,954	308,383
Total financial assets	12,297,629	6,426,614
Financial liabilities:
Policy liabilities - policyholder account balances	0	0
Funds withheld payable at interest	0	0
Debt obligations	0	0
Securities sold under agreements to repurchase	0	0
Total financial liabilities	0	0
Insurance | Fair Value | Level II
Financial assets:
Mortgage and other loan receivables	0	0
Policy loans	0	0
FHLB common stock and other investments	0	0
Funds withheld receivables at interest	2,624,984	2,855,251
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Total financial assets	2,624,984	2,855,251
Financial liabilities:
Policy liabilities - policyholder account balances	45,395,423	38,328,025
Funds withheld payable at interest	36,786,825	26,227,183
Debt obligations	0	0
Securities sold under agreements to repurchase	1,358,434	805,316
Total financial liabilities	83,540,682	65,360,524
Insurance | Fair Value | Level III
Financial assets:
Mortgage and other loan receivables	35,539,059	31,256,107
Policy loans	1,341,005	789,726
FHLB common stock and other investments	173,148	163,289
Funds withheld receivables at interest	0	0
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Total financial assets	37,053,212	32,209,122
Financial liabilities:
Policy liabilities - policyholder account balances	6,966,991	7,383,537
Funds withheld payable at interest	0	0
Debt obligations	2,396,587	1,698,526
Securities sold under agreements to repurchase	0	0
Total financial liabilities	$ 9,363,578	$ 9,082,063