INVESTMENTS - Additional Information (Detail) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2023 USD ($)		Sep. 30, 2022 USD ($)		Sep. 30, 2023 USD ($) investment		Sep. 30, 2022 USD ($) investment		Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
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)	$ 47				$ 13
Transitional real estate loan commitments	661				661
Middle market loan program unfunded amount	19				19					$ 28
Middle market loan commitments	745				745
Amortized Cost	16,904				16,904					19,063
Loan commitments, allowance for credit loss	19		$ 26		19		$ 26
Limited partnerships investment commitments	$ 2,400				$ 2,400
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%				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%				100.00%
Securities Lending, Securities Received as Collateral	$ 5,100				$ 5,100					6,800
Repurchase Agreements and Repurchase-to-Maturity Transactions Outstanding	0				0					0
Credit allowance	260				260					192
Nonaccrual loans, interest income	0				0
Financing receivable, before allowance for credit loss	13,133				13,133					13,688
Real estate owned, amount of loss at acquisition	(53)		0		(53)		0
Real estate owned, held-for-sale	16				16
Real estate owned, held-and-used	73				73
Other investments	5,241				5,241					4,070
Real estate owned
Schedule of Investments [Line Items]
Other investments	89				89					0
Transitional real estate loans
Schedule of Investments [Line Items]
Nonaccrual loans, no allowance	65				65
Financing receivable, before allowance for credit loss	6,550				6,550
Real estate owned, amount of loss at acquisition	(53)				(53)
Amortized cost of foreclosure or deed in lieu foreclosure	142				142
Transitional real estate loans | Potential Foreclosure or Deed-in-lieu Foreclosure
Schedule of Investments [Line Items]
Credit allowance	35				35
Financing receivable, before allowance for credit loss	481				481
Amortized cost of financing receivable in anticipation of foreclosure	546				546
Middle market loans
Schedule of Investments [Line Items]
Nonaccrual loans, no allowance	0				0
Financing receivable, before allowance for credit loss	4,849				4,849
Transitional real estate loans
Schedule of Investments [Line Items]
Credit allowance	111	[1]	$ 55	[1]	111	[1]	$ 55	[1]	$ 76	54	$ 53	$ 68
Financing receivable, before allowance for credit loss	6,550				6,550					$ 6,509
Zero-credit-loss expectation | Japan government and agencies
Schedule of Investments [Line Items]
Amortized Cost	$ 16,100				$ 16,100
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					13.00%
FLORIDA | Commercial Mortgage and Transitional Real Estate Loans | Mortgages
Schedule of Investments [Line Items]
Concentration Risk, Percentage					10.00%

[1] Excludes allowance on firm loan commitments of $19 and $26 as of September 30, 2023 and 2022, respectively.