INVESTMENTS - Fair Value and Gross Unrealized Losses for Securities That Have Been in Continuous Unrealized Loss Position (Detail) - Fixed maturity securities - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	$ 24,984	$ 7,914
Total Unrealized Losses	2,441	239
Less than 12 months Fair Value	19,642	2,948
Less than 12 months Unrealized Losses	1,672	42
12 months or Longer Fair Value	5,342	4,966
12 months or Longer Unrealized Losses	769	197
Dollar-denominated | U.S. government and agencies
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1	1
Total Unrealized Losses	5	1
Less than 12 months Fair Value	0	0
Less than 12 months Unrealized Losses	5	1
12 months or Longer Fair Value	1	1
12 months or Longer Unrealized Losses	0	0
Dollar-denominated | Municipalities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	719	82
Total Unrealized Losses	48	2
Less than 12 months Fair Value	701	79
Less than 12 months Unrealized Losses	43	2
12 months or Longer Fair Value	18	3
12 months or Longer Unrealized Losses	5	0
Dollar-denominated | Mortgage- and asset-backed securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	784	278
Total Unrealized Losses	53	2
Less than 12 months Fair Value	758	278
Less than 12 months Unrealized Losses	51	2
12 months or Longer Fair Value	26	0
12 months or Longer Unrealized Losses	2	0
Dollar-denominated | Public utilities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,044	130
Total Unrealized Losses	91	5
Less than 12 months Fair Value	1,005	70
Less than 12 months Unrealized Losses	86	2
12 months or Longer Fair Value	39	60
12 months or Longer Unrealized Losses	5	3
Dollar-denominated | Sovereign and supranational
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	31	37
Total Unrealized Losses	12	6
Less than 12 months Fair Value	5	6
Less than 12 months Unrealized Losses	2	1
12 months or Longer Fair Value	26	31
12 months or Longer Unrealized Losses	10	5
Dollar-denominated | Banks/financial institutions
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	754	292
Total Unrealized Losses	62	3
Less than 12 months Fair Value	684	274
Less than 12 months Unrealized Losses	53	3
12 months or Longer Fair Value	70	18
12 months or Longer Unrealized Losses	9	0
Dollar-denominated | Other corporate
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	6,549	1,365
Total Unrealized Losses	645	53
Less than 12 months Fair Value	5,912	458
Less than 12 months Unrealized Losses	515	8
12 months or Longer Fair Value	637	907
12 months or Longer Unrealized Losses	130	45
Yen-denominated | Japan government and agencies
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	8,816	2,868
Total Unrealized Losses	903	61
Less than 12 months Fair Value	5,552	445
Less than 12 months Unrealized Losses	454	3
12 months or Longer Fair Value	3,264	2,423
12 months or Longer Unrealized Losses	449	58
Yen-denominated | Municipalities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	306	187
Total Unrealized Losses	32	5
Less than 12 months Fair Value	205	53
Less than 12 months Unrealized Losses	16	0
12 months or Longer Fair Value	101	134
12 months or Longer Unrealized Losses	16	5
Yen-denominated | Mortgage- and asset-backed securities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	65	33
Total Unrealized Losses	6	1
Less than 12 months Fair Value	40	0
Less than 12 months Unrealized Losses	3	0
12 months or Longer Fair Value	25	33
12 months or Longer Unrealized Losses	3	1
Yen-denominated | Public utilities
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	761	26
Total Unrealized Losses	52	2
Less than 12 months Fair Value	716	0
Less than 12 months Unrealized Losses	47	0
12 months or Longer Fair Value	45	26
12 months or Longer Unrealized Losses	5	2
Yen-denominated | Sovereign and supranational
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	71
Total Unrealized Losses	2
Less than 12 months Fair Value	35
Less than 12 months Unrealized Losses	2
12 months or Longer Fair Value	36
12 months or Longer Unrealized Losses	0
Yen-denominated | Banks/financial institutions
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	3,421	2,074
Total Unrealized Losses	343	72
Less than 12 months Fair Value	2,576	1,011
Less than 12 months Unrealized Losses	246	16
12 months or Longer Fair Value	845	1,063
12 months or Longer Unrealized Losses	97	56
Yen-denominated | Other corporate
Investments, Unrealized Loss Position [Line Items]
Total Fair Value	1,662	541
Total Unrealized Losses	187	26
Less than 12 months Fair Value	1,453	274
Less than 12 months Unrealized Losses	149	4
12 months or Longer Fair Value	209	267
12 months or Longer Unrealized Losses	$ 38	$ 22