POLICY LIABILITIES - Reconciliation of Future Policy Benefits (Detail) - USD ($) $ in Millions		Dec. 31, 2023	Dec. 31, 2022
Liability for Future Policy Benefit, Activity [Line Items]
Deferred reinsurance gain liability		$ 175	$ 692
Future policy benefits		83,718	88,241
Segment Reconciling Items
Liability for Future Policy Benefit, Activity [Line Items]
Deferred profit liability - limited-payment contracts		1,806	1,740
Deferred reinsurance gain liability		1,012	692
Intercompany eliminations
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits	[1]	(5,017)	(667)
Corporate and other | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		4,225	686
Cancer | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		32,652	35,468
Cancer | Aflac Japan | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		32,652	35,468
Medical and other health | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		10,560	10,705
Medical and other health | Aflac Japan | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		10,560	10,705
Life insurance | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		23,243	24,469
Life insurance | Aflac Japan | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		23,243	24,469
Life insurance | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		911	802
Life insurance | Aflac U.S. | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		911	802
Accident | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		621	564
Accident | Aflac U.S. | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		621	564
Disability | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		770	810
Disability | Aflac U.S. | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		770	810
Critical care | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		7,216	7,003
Critical care | Aflac U.S. | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		7,216	7,003
Hospital indemnity | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		836	854
Hospital indemnity | Aflac U.S. | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		836	854
Dental/vision | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		272	277
Dental/vision | Aflac U.S. | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		272	277
Other | Aflac Japan
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		4,090	4,326
Other | Aflac Japan | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		4,090	4,326
Other | Aflac U.S.
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		521	512
Other | Aflac U.S. | Operating Segments
Liability for Future Policy Benefit, Activity [Line Items]
Future policy benefits		$ 521	$ 512

[1] Elimination entry necessary due to the internal reinsurance transactions with Aflac Re and to recapture a portion of policy liabilities ceded externally as a result of the reinsurance retrocession transaction. See Note 8 for additional details