BUSINESS SEGMENT INFORMATION - Operations by Segment - Pretax Earnings (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Other income (loss)		$ 0	$ 35	$ (2)	$ 35
Net investment gains (losses)		696	555	1,647	678
Earnings before income taxes		2,019	1,825	4,190	3,167
Income taxes applicable to pretax adjusted earnings		235	186	438	366
Effect of foreign currency translation on after-tax adjusted earnings		(37)	(25)	(81)	(66)
Remeasurement gain (loss), deferred profit liability for limited-payment contracts		(2)	(1)	(5)	(1)
Operating Segments
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings		1,270	1,139	2,434	2,273
Segment Reconciling Items
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [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
Impact of interest from derivatives associated with notes payable		(9)	(8)	(17)	(22)
Aflac Japan | Operating Segments
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings	[1]	864	822	1,674	1,610
Aflac U.S. | Operating Segments
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings		383	369	739	721
Corporate and other
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [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, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings	[2]	$ 23	$ (52)	$ 21	$ (58)

[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.