BUSINESS SEGMENT INFORMATION - Operations by Segment - Revenues (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums	[1]	$ 3,325	$ 3,573	$ 6,781	$ 7,262
Net investment income		1,095	999	2,095	1,942
Other income		22	45	52	90
Total revenues		5,138	5,172	10,575	9,972
Net investment gains (losses)		696	555	1,647	678
Remeasurement gain (loss), deferred profit liability for limited-payment contracts		(2)	(1)	(5)	(1)
Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues		4,380	4,513	8,800	9,091
Segment Reconciling Items
Segment Reporting, Revenue Reconciling Item [Line Items]
Amortized hedge costs		7	63	13	122
Amortized hedge income		(34)	(38)	(62)	(67)
Net interest (income) expense from from derivatives associated with certain investment strategies		89	79	177	148
Aflac Japan | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums	[1]	1,715	2,064	3,531	4,234
Net investment income		725	637	1,374	1,248
Other income		7	9	14	18
Total revenues		2,447	2,710	4,919	5,500
Aflac U.S. | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Net earned premiums		1,455	1,425	2,930	2,853
Net investment income		218	203	424	400
Other income		11	35	30	70
Total revenues		1,684	1,663	3,384	3,323
Corporate and other
Segment Reporting, Revenue Reconciling Item [Line Items]
Change in value of federal historic rehabilitation and solar tax credit investments		(30)	(53)	(62)	(105)
Federal historic rehabilitation and solar tax credits, amount		31	56	64	108
Corporate and other | Operating Segments
Segment Reporting, Revenue Reconciling Item [Line Items]
Total revenues	[2]	$ 249	$ 140	$ 497	$ 268

[1] Includes a gain (loss) of $(2) and $(1) for the three-month periods and $(5) and $(1) for the six-month periods ended June 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 $30 and $53 for the three-month periods and $62 and $105 for the six-month periods ended June 30, 2024, and 2023, respectively, is included as a reduction to net investment income. Tax credits on these investments of $31 and $56 for the three-month periods and $64 and $108 for the six-month periods ended June 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.