INCOME TAXES - Income Tax Effects of Temporary Differences that Gave Rise to Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred income tax liabilities:
Deferred policy acquisition costs	$ 3,262	$ 3,663
Unrealized gains and other basis differences on investments	5,313	5,227
Foreign currency gain on Aflac Japan	0	70
Premiums receivable	66	112
Policy benefit reserves	3,578	3,834
Total deferred income tax liabilities	12,219	12,906
Deferred income tax assets:
Unfunded retirement benefits	7	9
Other accrued expenses	38	37
Policy and contract claims	794	868
Foreign currency loss on Aflac Japan	91	0
Deferred compensation	104	137
Capital loss carryforwards	0	12
Depreciation	230	202
Anticipatory foreign tax credit	5,883	5,972
Deferred foreign tax credit	701	647
Other	163	326
Total deferred income tax assets	8,011	8,210
Net deferred income tax liability	4,208	4,696
Current income tax liability	131
Current income tax asset		(35)
Total income tax liability	$ 4,339	$ 4,661