BUSINESS SEGMENT AND SELECTED FOREIGN CURRENCY TRANSLATION ITEMS - Operations by Segment - Revenues (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums	[1]	$ 13,440	$ 14,123	$ 14,901
Net investment income		4,116	3,811	3,656
Other income (loss)		100	177	220
Total revenues		18,927	18,701	19,140
Net investment gains (losses)		1,271	590	363
Remeasurement gain (loss), deferred profit liability for limited-payment contracts		(81)	20	(42)
Change in value of federal historic rehabilitation and solar tax credit investments		(165)	(343)	(91)
Federal historic rehabilitation and solar tax credits, amount		164	334	83
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		17,405	17,747	18,643
Segment Reconciling Items
Segment Reporting, Revenue Reconciling Item [Line Items]
Net investment gains (losses)		1,271	590	363
Amortized hedge costs		26	157	112
Amortized hedge income		(113)	(121)	(68)
Net interest (income) expense from derivatives associated with certain investment strategies		338	328	90
Aflac Japan
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums		6,930	8,047	9,186
Net investment income		3,032	3,033	2,867
Aflac Japan | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums	[1]	6,930	8,047	9,186
Net investment income		2,701	2,582	2,669
Other income (loss)		28	35	35
Total revenues	[1]	9,659	10,664	11,890
Aflac U.S.
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums		5,829	5,675	5,570
Net investment income		883	854	759
Aflac U.S. | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums		5,829	5,675	5,570
Net investment income		847	820	755
Other income (loss)		63	128	161
Total revenues		6,739	6,623	6,486
Corporate and other
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums		681	400	145
Net investment income		201	(77)	30
Corporate and other | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	[2]	$ 1,007	$ 460	$ 267

[1] Includes a gain (loss) of $(81), $20 and $(42) in 2024, 2023 and 2022, respectively, related to remeasurement of the deferred profit liability for limited-payment contracts.

[2] The change in value of federal historic rehabilitation and solar investments in partnerships of $165, $343 and $91 in 2024, 2023 and 2022, respectively, is included as a reduction to net investment income. Tax credits on these investments of $164, $334 and $83 in 2024, 2023 and 2022, respectively, have been recorded as an income tax benefit in the consolidated statements of earnings. See Note 3 for additional information on these investments.