SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Summary of Signficant Accounting Policies - Additional Information (Detail) $ in Millions		12 Months Ended
		Dec. 31, 2022 USD ($) segment		Dec. 31, 2021 USD ($)		Dec. 31, 2020 USD ($)	Jan. 01, 2023 USD ($)	Jan. 01, 2021 USD ($)	Jan. 01, 2020 USD ($)	Dec. 31, 2019 USD ($)
Significant Accounting Policies [Line Items]
Number of reportable insurance business segments | segment		2
Goodwill		$ 265		$ 268
Stockholders' Equity Attributable to Parent		22,365		33,253		$ 33,559				$ 28,959
Accumulated Other Comprehensive Income (Loss), Net of Tax		(4,405)		7,393		$ 8,934				6,615
Retained earnings		44,568		41,381
Amortized Cost		75,469		85,369
Held-to-maturity securities		$ (19,063)		$ (22,008)
Aflac Japan
Significant Accounting Policies [Line Items]
Percentage of the Company's total revenues		69.00%		69.00%		68.00%
Percentage of the Company's total assets		80.00%		82.00%
Accounting Standards Update 2019-04
Significant Accounting Policies [Line Items]
New accounting pronouncement or change in accounting principle effect of adoption unrealized gain loss net of tax reclassification to accumulated other comprehensive income									$ 848
Accounting Standards Update 2019-04 | Revision of Prior Period, Accounting Standards Update, Adjustment
Significant Accounting Policies [Line Items]
Amortized Cost						$ 6,900
Held-to-maturity securities						6,900
Accounting Standards Update 2019-04 | Cumulative effect, period of adoption, adjustment
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent	[1]									848
Accumulated Other Comprehensive Income (Loss), Net of Tax										848
Accounting Standards Update 2016-13 | Cumulative effect, period of adoption, adjustment
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent	[1]									(56)
Accounting Standards Update 2018-12 | Pro Forma
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent		$ 20,140		$ 17,031
Retained earnings		44,367	[2]	40,963	[3]
Accounting Standards Update 2018-12 | Cumulative effect, period of adoption, adjustment | Pro Forma
Significant Accounting Policies [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax								$ (18,600)
Retained earnings								$ (300)
Accounting Standards Update 2018-12 | Cumulative effect, period of adoption, adjustment | Forecast
Significant Accounting Policies [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax							$ (2,100)
Accumulated other comprehensive income (loss)
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent		(4,405)		7,393		8,934				6,615
Accumulated other comprehensive income (loss) | Accounting Standards Update 2019-04 | Cumulative effect, period of adoption, adjustment
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent	[1]									848
Accumulated other comprehensive income (loss) | Accounting Standards Update 2016-13 | Cumulative effect, period of adoption, adjustment
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent	[1]									0
Retained earnings
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent		$ 44,568		$ 41,381		$ 37,984				34,291
Retained earnings | Accounting Standards Update 2019-04 | Cumulative effect, period of adoption, adjustment
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent	[1]									0
Retained earnings | Accounting Standards Update 2016-13 | Cumulative effect, period of adoption, adjustment
Significant Accounting Policies [Line Items]
Stockholders' Equity Attributable to Parent									$ (56)	$ (56)	[1]

[1] See Note 1 of the Notes to the Consolidated Financial Statements for the adoption of accounting guidance on January 1, 2020.

[2] Adjustment reflects the cumulative impact from adoption and post-adoption activity under the updated standard, including the increase in 2022 net earnings of $217.

[3] Adjustment reflects the impacts from adoption of ($324) as a result of capping the net premium ratio at 100% for cohorts that are in a loss position at transition and post-adoption activity under the updated standard, including the decrease in 2021 net earnings of $(94).