ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - CUMMULATIVE GAINS (LOSSES) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income	$ 14,902	$ 16,946	$ 18,492	$ 19,492	$ 16,086	$ 16,180	$ 14,421	$ 14,528	$ 15,552
Unrealized gains (losses) on investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income	(839)				369
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income	(47)				(57)
Defined benefit pension plans
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income	(59)				(48)
Total accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income	(945)				264
Less: Accumulated other comprehensive (income) loss attributable to noncontrolling interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income	78				67
Accumulated other comprehensive income (loss) attributable to AXA Equitable
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income	$ (867)			$ 598	$ 331			$ (4)