INCOME TAXES - Income Tax Effects of Temporary Differences that Gave Rise to Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Deferred income tax liabilities:
Deferred policy acquisition costs	$ 3,663	$ 3,492
Unrealized gains and other basis differences on investments	5,227	4,485
Deferred Tax Liabilities, Unrealized Currency Transaction Gains	70	0
Premiums receivable	112	152
Policy benefit reserves	3,834	3,442
Total deferred income tax liabilities	12,906	11,571
Deferred income tax assets:
Unfunded retirement benefits	9	8
Other accrued expenses	37	36
Policy and contract claims	868	781
Foreign currency loss on Aflac Japan	0	16
Deferred compensation	137	162
Capital loss carryforwards	12	34
Depreciation	202	164
Anticipatory foreign tax credit	5,972	5,487
Deferred foreign tax credit	647	605
Other	326	204
Total deferred income tax assets before valuation allowance	8,210	7,497
Valuation allowance	0	(1,340)
Total deferred income tax assets after valuation allowance	8,210	6,157
Net deferred income tax liability	4,696	5,414
Current income tax asset	(35)	(44)
Total income tax liability	$ 4,661	$ 5,370