BUSINESS SEGMENT INFORMATION - Operations by Segment - Revenues (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums	[1]	$ 3,328	$ 3,476	$ 10,109	$ 10,737
Net investment income		1,006	1,004	3,100	2,946
Other income		23	47	76	139
Total revenues		2,949	4,950	13,524	14,923
Net investment gains (losses)		(1,408)	423	239	1,101
Remeasurement gain (loss), deferred profit liability for limited-payment contracts		(75)	22	(80)	22
Change in value of federal historic rehabilitation and solar tax credit investments		(57)	(64)	(119)	(169)
Federal historic rehabilitation and solar tax credits, amount		78	63	142	171
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		4,287	4,436	13,088	13,527
Segment Reconciling Items
Segment Reporting, Revenue Reconciling Item [Line Items]
Net investment gains (losses)		(1,408)	423	239	1,101
Amortized hedge costs		7	26	19	148
Amortized hedge income		(25)	(25)	(87)	(92)
Net interest (income) expense from from derivatives associated with certain investment strategies		88	90	265	239
Aflac Japan | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums	[1]	1,709	1,973	5,241	6,207
Net investment income		662	679	2,036	1,927
Other income		7	8	20	26
Total revenues		2,378	2,660	7,297	8,160
Aflac U.S. | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums		1,459	1,419	4,388	4,272
Net investment income		210	209	634	609
Other income		15	33	46	102
Total revenues		1,684	1,661	5,068	4,983
Corporate and other | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	[2]	$ 225	$ 115	$ 723	$ 384

[1] Includes a gain (loss) of $(75) and $22 for the three-month periods and $(80) and $22 for the nine-month periods ended September 30, 2024 and 2023, 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 $57 and $64 for the three-month periods and $119 and $169 for the nine-month periods ended September 30, 2024, and 2023, respectively, is included as a reduction to net investment income. Tax credits on these investments of $78 and $63 for the three-month periods and $142 and $171 for the nine-month periods ended September 30, 2024, and 2023, respectively, have been recorded as an income tax benefit in the consolidated statements of earnings. See Note 3 for additional information on these investments.