BUSINESS SEGMENT AND SELECTED FOREIGN CURRENCY TRANSLATION ITEMS - Operations by Segment - Pretax Earnings (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues		$ 18,927	$ 18,701	$ 19,140
Benefits and claims, excluding reserve remeasurement		8,008	8,594	9,102
Reserve remeasurement (gains) losses		(558)	(383)	(215)
Benefits and claims, net		7,450	8,211	8,887
Amortization of deferred policy acquisition costs		851	816	792
Insurance commissions		998	1,052	1,117
Insurance and other expenses		3,014	3,165	3,249
Total benefits and expenses		12,510	13,439	14,271
Net investment gains (losses)		1,271	590	363
Earnings before income taxes		6,417	5,262	4,869
Income taxes applicable to pretax adjusted earnings		873	577	808
Effect of foreign currency translation on after-tax adjusted earnings		(103)	(113)	(262)
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, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues		17,405	17,747	18,643
Total benefits and expenses		12,460	13,437	14,221
Pretax adjusted earnings		4,945	4,310	4,422
Segment Reconciling Items
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Other income (loss)		(23)	39	0
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
Impact of interest from derivatives associated with notes payable		(27)	(41)	(50)
Aflac Japan
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Benefits and claims, net		4,317	5,313	6,191
Amortization of deferred policy acquisition costs		321	326	338
Aflac Japan | Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	[1]	9,659	10,664	11,890
Benefits and claims, excluding reserve remeasurement		4,761	5,409	6,282
Reserve remeasurement (gains) losses		(444)	(96)	(91)
Benefits and claims, net		4,317	5,313	6,191
Amortization of deferred policy acquisition costs		321	326	338
Insurance commissions		435	491	563
Insurance and other expenses		1,092	1,300	1,517
Total benefits and expenses		6,165	7,430	8,609
Pretax adjusted earnings	[1]	3,494	3,234	3,281
Aflac U.S.
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Benefits and claims, net		2,726	2,431	2,555
Amortization of deferred policy acquisition costs		530	490	455
Aflac U.S. | Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues		6,739	6,623	6,486
Benefits and claims, excluding reserve remeasurement		2,821	2,715	2,679
Reserve remeasurement (gains) losses		(95)	(284)	(124)
Benefits and claims, net		2,726	2,431	2,555
Amortization of deferred policy acquisition costs		530	490	455
Insurance commissions		563	561	553
Insurance and other expenses		1,501	1,640	1,564
Total benefits and expenses		5,320	5,122	5,127
Pretax adjusted earnings		1,419	1,501	1,359
Corporate and other
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Benefits and claims, net		407	467	141
Amortization of deferred policy acquisition costs		0	0	0
Corporate and other | Operating Segments
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Total revenues	[2]	1,007	460	267
Total benefits and expenses		975	885	485
Pretax adjusted earnings	[2]	$ 32	$ (425)	$ (218)

[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.