BUSINESS SEGMENT INFORMATION - Operations by Segment - Pretax Earnings (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Net investment gains (losses)		$ (1,408)	$ 423	$ 239	$ 1,101
Earnings before income taxes		92	1,805	4,282	4,972
Income taxes applicable to pretax adjusted earnings		227	203	665	570
Effect of foreign currency translation on after-tax adjusted earnings		(16)	(33)	(97)	(100)
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, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings		1,438	1,298	3,872	3,571
Segment Reconciling Items
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Other income (loss)		0	3	(1)	38
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
Impact of interest from derivatives associated with notes payable		(8)	(10)	(25)	(33)
Aflac Japan | Operating Segments
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings	[1]	1,073	869	2,747	2,479
Aflac U.S. | Operating Segments
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings		350	478	1,089	1,199
Corporate and other | Operating Segments
Segment Reporting, Reconciling Item for Adjusted Profit (Loss) from Segment to Consolidated [Line Items]
Pretax adjusted earnings	[2]	$ 15	$ (49)	$ 36	$ (107)

[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.