INVESTMENTS - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($) investment	Mar. 31, 2023 USD ($) investment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Schedule of Investments [Line Items]
Held to maturity securities transferred to available for sale securities, number of investments | investment	0	0
Equity securities, FV-NI, unrealized gain (loss)	$ 71	$ (5)
Transitional real estate loan commitments	442
Middle market loan program unfunded amount	24		$ 24
Middle market loan commitments	787
Other loans commitments	5
Amortized Cost	16,694		17,824
Limited partnerships investment commitments	$ 2,200
Percentage that the lending policy requires that the fair value of the securities received as collateral be of the fair value of the loaned securities	102.00%
Percentage that the lending policy requires that the fair value of the unrestricted cash received as collateral be of the fair value of the loaned securities	100.00%
Securities Lending, Securities Received as Collateral	$ 4,500		4,300
Repurchase Agreements and Repurchase-to-Maturity Transactions Outstanding	0		0
Nonaccrual loans, interest income	0	0
Credit allowance	232		274
Financing receivable, before allowance for credit loss	12,592		12,801
Real estate owned, held-and-used			210
Real estate owned, held-for-sale			17
Depreciation expense	1
Accumulated depreciation	2
Other investments	6,677		4,530
Real estate owned
Schedule of Investments [Line Items]
Other investments	253		227
Transitional real estate loans
Schedule of Investments [Line Items]
Nonaccrual loans, no allowance	$ 383
Percent of total financing receivables	3.00%
Weighted-average interest rate before modification	8.30%
Weighted-average interest rate after modification	6.90%
Amortized cost of foreclosure or deed in lieu foreclosure	$ 31
Gains (loss) due to foreclosure	4
Amortized cost of financing receivable modified	210
Credit allowance	114	65	112	$ 54
Financing receivable, before allowance for credit loss	6,078		6,114
Transitional real estate loans | Potential Foreclosure or Deed-in-lieu Foreclosure
Schedule of Investments [Line Items]
Amortized cost of financing receivable in loan modification	601
Credit allowance	60
Financing receivable, before allowance for credit loss	598
Middle market loans
Schedule of Investments [Line Items]
Nonaccrual loans, no allowance	0		0
Credit allowance	99	$ 149	146	$ 129
Financing receivable, before allowance for credit loss	4,586		$ 4,677
Zero-credit-loss expectation | Japan government and agencies
Schedule of Investments [Line Items]
Amortized Cost	$ 15,900
CALIFORNIA | Commercial Mortgage and Transitional Real Estate Loans | Mortgages
Schedule of Investments [Line Items]
Concentration Risk, Percentage	20.00%
TEXAS | Commercial Mortgage and Transitional Real Estate Loans | Mortgages
Schedule of Investments [Line Items]
Concentration Risk, Percentage	15.00%
FLORIDA | Commercial Mortgage and Transitional Real Estate Loans | Mortgages
Schedule of Investments [Line Items]
Concentration Risk, Percentage	12.00%