Schedule II - Aflac Incorporated (Parent Only) - Condensed Balance Sheet (Detail 1) - USD ($) $ in Millions		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Investments and cash:
Available for sale, fixed maturity securities		$ 73,290	$ 75,741
Other investments		4,530	4,070
Cash and cash equivalents		4,306	3,943
Total investments and cash		113,560	117,397
Other assets		2,008	3,180
Assets		126,724	131,738
Liabilities:
Notes payable and lease obligations		7,364	7,442
Other Liabilities		4,119	4,739
Total liabilities		104,739	111,598
Shareholders' equity:
Common stock of $.10 par value. In thousands: authorized 1,900,000 shares in 2023 and 2022; issued 1,355,398 shares in 2023 and 1,354,079 shares in 2022		136	135
Additional paid-in capital		2,771	2,641
Retained earnings		47,993	44,367
Accumulated other comprehensive income (loss):
Unrealized foreign currency translation gains (losses)		(4,069)	(3,564)
Unrealized gains (losses) on fixed maturity securities		1,139	(702)
Unrealized gains (losses) on derivatives		(22)	(27)
Effect of changes in discount rate assumptions		(2,560)	(2,100)
Pension liability adjustment		(8)	(36)
Treasury stock, at average cost		(23,395)	(20,574)
Total shareholders’ equity		21,985	20,140	$ 17,031	$ 33,559
Total liabilities and shareholders' equity		126,724	131,738
Parent Company
Investments and cash:
Available for sale, fixed maturity securities		1,582	1,744
Investments in subsidiaries	[1]	24,508	22,972
Other investments		1,126	1,461
Cash and cash equivalents		1,007	1,143	$ 2,097	$ 2,126
Total investments and cash		28,223	27,320
Due from subsidiaries	[1]	270	267
Income taxes receivable		251	0
Other assets		1,202	964
Assets		29,946	28,551
Liabilities:
Employee benefit plans		329	291
Notes payable and lease obligations		6,819	7,069
Other Liabilities		813	1,051
Total liabilities		7,961	8,411
Shareholders' equity:
Common stock of $.10 par value. In thousands: authorized 1,900,000 shares in 2023 and 2022; issued 1,355,398 shares in 2023 and 1,354,079 shares in 2022		136	135
Additional paid-in capital		2,771	2,641
Retained earnings		47,993	44,367
Accumulated other comprehensive income (loss):
Unrealized foreign currency translation gains (losses)		(4,069)	(3,564)
Unrealized gains (losses) on fixed maturity securities		1,139	(702)
Unrealized gains (losses) on derivatives		(22)	(27)
Effect of changes in discount rate assumptions		(2,560)	(2,100)
Pension liability adjustment		(8)	(36)
Treasury stock, at average cost		(23,395)	(20,574)
Total shareholders’ equity		21,985	20,140
Total liabilities and shareholders' equity		$ 29,946	$ 28,551

[1] Eliminated in consolidation