INCOME TAXES - Income Tax Effects of Temporary Differences that Gave Rise to Deferred Income Tax Assets and Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred income tax liabilities:
Deferred policy acquisition costs	$ 3,285	$ 4,065
Unrealized gains and other basis differences on investment securities	2,882	3,056
Premiums receivable	104	130
Policy benefit reserves	3,557	3,303
Total deferred income tax liabilities	9,828	10,554
Deferred income tax assets:
Unfunded retirement benefits	8	13
Other accrued expenses	141	39
Policy and contract claims	870	792
Foreign currency loss on Japan branch	67	185
Deferred compensation	155	243
Capital loss carryforwards	0	3
Depreciation	114	88
Anticipatory foreign tax credit	4,504	4,028
Other	57	107
Total deferred income tax assets before valuation allowance	5,916	5,498
Valuation allowance	(657)	0
Total deferred income tax assets after valuation allowance	5,259	5,498
Net deferred income tax liability	4,569	5,056
Current income tax liability	176	331
Total income tax liability	$ 4,745	$ 5,387