SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)

12 Months Ended

Dec. 31, 2023

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Schedule of Impact from Adoption to Shareholder's Equity

The following table presents the cumulative transition impact as of January 1, 2021 to the Company’s shareholders' equity as a result of the adoption of ASU 2018-12, using the modified retrospective transition method.

(In millions - Unaudited)	Common Stock		Additional Paid-in Capital		Retained Earnings		Accumulated Other Comprehensive Income (Loss)		Treasury Stock		Total Shareholders' Equity
Balance at December 31, 2020	$	135	$	2,410	$	37,984	$	8,934	$	(15,904)	$	33,559
Cumulative effect of change in accounting   principle, ASU 2018-12, net of income taxes	0		0		(324)		(18,570)		0		(18,894)
Balance at January 1, 2021	$	135	$	2,410	$	37,660	$	(9,636)	$	(15,904)	$	14,665

Accounting Standards Update 2018-12

New Accounting Pronouncements or Change in Accounting Principle [Line Items]

Schedule of Impact from Adoption to AOCI and Retained Earnings

The following table presents the transition impacts as of January 1, 2021 to the Company's AOCI and RE as a result of the adoption of ASU 2018-12 by reporting segment and disaggregated by product type, using the modified retrospective transition method.

(In millions - Unaudited)	Impact to Retained Earnings			Impact to AOCI
Transition impacts:
Aflac Japan
Cancer		$	0		$	14,529
Medical and other health		1			2,382
Life insurance		0			3,314
Other (1)		398			433
Aflac U.S.
Accident		0			92
Disability		0			149
Critical care		4			2,258
Hospital indemnity		0			223
Dental/vision		0			65
Life insurance		5			149
Other		2			218
Reinsurance		0			(305)
Transition impact before income taxes		410			23,507
Less: income taxes		86			4,937
Total transition impact, net of income taxes		$	324		$	18,570

(1) Impact to retained earnings is driven primarily by capping the Transition Date NPR on Care products.

Schedule of Impact from Adoption to Liability For Future Policy Benefit, Expected Net Premium

The following table presents the transition impacts to the present value of expected future net premiums, gross of internal and external ceded reinsurance, by reporting segment and disaggregated by product type due to the cumulative effect of the change in accounting principle as a result of the adoption of ASU 2018-12 using the modified retrospective transition method.

	Transition Impact at January 1, 2021
	Aflac Japan								Aflac U.S.
(In millions)	Cancer		Medical and Other Health		Life Insurance		Other		Accident		Disability		Critical Care		Hospital Indemnity		Dental/Vision		Life Insurance		Other
Present value of expected future net premiums:
Balance at December 31, 2020	$	25,601	$	21,270	$	12,440	$	2,080	$	3,350	$	1,921	$	5,898	$	1,376	$	281	$	710	$	154
Impact to retained earnings from capping Transition Date NPR	0		(1)		0		(398)		0		0		(4)		0		0		(5)		(2)
Impact of deferred profit liability	15		7		36		26		0		0		0		0		0		0		0
Beginning balance at original discount rate	25,616		21,276		12,476		1,708		3,350		1,921		5,894		1,376		281		705		152
Effect of change in discount rate assumptions	3,982		2,598		908		148		479		197		1,048		154		41		78		27
Balance at January 1, 2021	$	29,598	$	23,874	$	13,384	$	1,856	$	3,829	$	2,118	$	6,942	$	1,530	$	322	$	783	$	179

Liability for Future Policy Benefit, Expected Net Premium, Activity

The following table presents the changes in the present value of expected future net premiums, gross of internal and external reinsurance, by reporting segment and disaggregated by product type for the year ended December 31, 2021.

	December 31, 2021
	Aflac Japan								Aflac U.S.
(In millions)	Cancer		Medical and Other Health		Life Insurance		Other		Accident		Disability		Critical Care		Hospital Indemnity		Dental/Vision		Life Insurance		Other
Present value of expected future net premiums:
Balance at January 1, 2021	$	29,598	$	23,874	$	13,384	$	1,856	$	3,829	$	2,118	$	6,942	$	1,530	$	322	$	783	$	179
Beginning balance at original discount rate (1)	25,616		21,276		12,476		1,708		3,350		1,921		5,894		1,376		281		705		152
Effect of changes in cash flow assumptions	32		88		40		1		(163)		(129)		(302)		0		(26)		31		0
Effect of actual variances from expected   experience	(134)		(449)		(135)		(11)		(109)		(38)		(290)		(32)		(14)		34		(3)
Adjusted beginning of period balance	25,514		20,915		12,381		1,698		3,078		1,754		5,302		1,344		241		770		149
Issuances	1,116		1,132		284		55		365		345		552		263		39		112		0
Interest accrual	586		439		202		27		116		61		210		45		10		25		6
Net premiums collected (2)	(2,206)		(1,692)		(1,609)		(151)		(552)		(393)		(665)		(268)		(47)		(124)		(19)
Foreign currency translation	(2,539)		(2,111)		(1,194)		(167)		0		0		0		0		0		0		0
Other	(1)		(2)		0		(1)		(8)		(7)		(8)		(4)		(2)		(3)		(1)
Ending balance at original discount rate	22,470		18,681		10,064		1,461		2,999		1,760		5,391		1,380		241		780		135
Effect of changes in discount rate assumptions	3,423		2,493		783		125		284		102		632		87		23		54		18
Balance at December 31, 2021	$	25,893	$	21,174	$	10,847	$	1,586	$	3,283	$	1,862	$	6,023	$	1,467	$	264	$	834	$	153

(1) Includes the adjustment for capping the Transition Date NPR.

(2) Net premiums collected represent the portion of gross premiums collected from policyholders that is used to fund expected future benefit payments.

Schedule of Impact from Adoption to Liability For Future Policy Benefit, Expected Future Policy Benefits

The following table presents the transition impacts to the present value of expected future policy benefits by reporting segment and disaggregated by product type due to the cumulative effect of the change in accounting principle as a result of the adoption of ASU 2018-12 using the modified retrospective transition method.

	Transition Impact at January 1, 2021
	Aflac Japan								Aflac U.S.
(In millions)	Cancer		Medical and Other Health		Life Insurance		Other		Accident		Disability		Critical Care		Hospital Indemnity		Dental/Vision		Life Insurance		Other
Present value of expected future policy benefits:
Balance at December 31, 2020	$	64,056	$	34,638	$	43,729	$	7,620	$	3,818	$	2,919	$	13,427	$	2,258	$	599	$	1,562	$	661
Effect of change in discount rate assumptions	18,511		4,980		4,222		581		571		346		3,306		377		106		227		245
Balance at January 1, 2021	$	82,567	$	39,618	$	47,951	$	8,201	$	4,389	$	3,265	$	16,733	$	2,635	$	705	$	1,789	$	906

Liability for Future Policy Benefit, Expected Future Policy Benefit, Activity

The following table presents the changes in the present value of expected future policy benefits by reporting segment and disaggregated by product type for the year ended December 31, 2021.

	December 31, 2021
	Aflac Japan								Aflac U.S.
(In millions)	Cancer		Medical and Other Health		Life Insurance		Other		Accident		Disability		Critical Care		Hospital Indemnity		Dental/Vision		Life Insurance		Other
Present value of expected future policy benefits:
Balance at January 1, 2021	$	82,567	$	39,618	$	47,951	$	8,201	$	4,389	$	3,265	$	16,733	$	2,635	$	705	$	1,789	$	906
Beginning balance at original discount rate	64,056		34,638		43,729		7,620		3,818		2,919		13,427		2,258		599		1,562		661
Effect of changes in cash flow assumptions	24		85		31		(11)		(178)		(143)		(326)		(3)		(29)		31		0
Effect of actual variances from expected   experience	(149)		(458)		(139)		(15)		(115)		(41)		(304)		(36)		(15)		34		(3)
Adjusted beginning of period balance	63,931		34,265		43,621		7,594		3,525		2,735		12,797		2,219		555		1,627		658
Issuances	1,133		1,155		287		62		372		355		563		271		40		115		0
Interest accrual	2,014		769		833		129		137		100		553		85		23		58		33
Benefit payments	(3,894)		(1,313)		(1,373)		(238)		(439)		(520)		(834)		(275)		(69)		(107)		(46)
Foreign currency translation	(6,377)		(3,478)		(4,366)		(760)		0		0		0		0		0		0		0
Other	0		0		0		0		(1)		0		0		0		0		1		0
Ending balance at original discount rate	56,807		31,398		39,002		6,787		3,594		2,670		13,079		2,300		549		1,694		645
Effect of changes in discount rate assumptions	15,940		4,623		3,718		535		355		201		2,309		252		67		149		192
Balance at December 31, 2021	72,747		36,021		42,720		7,322		3,949		2,871		15,388		2,552		616		1,843		837
Net liability for future policy benefits	46,854		14,847		31,873		5,736		666		1,009		9,365		1,085		352		1,009		684
Less: reinsurance recoverable	0		2,150		0		0		0		0		0		0		0		10		0
Net liability for future policy benefits after   reinsurance recoverable	$	46,854	$	12,697	$	31,873	$	5,736	$	666	$	1,009	$	9,365	$	1,085	$	352	$	999	$	684

Reconciliation of Future Policy Benefits Year of Adoption

The following table presents a reconciliation of the rollforwards by reporting segment and disaggregated by product type for the year ended December 31, 2021 to the liability for future policy benefits as of December 31, 2021 under the amended guidance. The deferred profit liability for limited-payment contracts and the deferred reinsurance gain liability is presented together with the LFPB in the consolidated balance sheets and has been included as a reconciling item in the table below.

(In millions)	December 31, 2021
Balances included in future policy benefits rollforward:
Aflac Japan
Cancer		$	46,854
Medical and other health		14,847
Life insurance		31,873
Other		5,736
Aflac U.S.
Accident		666
Disability		1,009
Critical care		9,365
Hospital indemnity		1,085
Dental/vision		352
Life insurance		1,009
Other		684
Corporate and other		30
Deferred profit liability		1,595
Deferred reinsurance gain liability		859
Total		$	115,964