SIGNIFICANT ACCOUNTING POLICIES - Variable Interest Entities (Details) $ in Millions		6 Months Ended	12 Months Ended
		Jun. 30, 2020 USD ($) joint_venture	Dec. 31, 2019 USD ($) joint_venture
Variable Interest Entity [Line Items]
Assets		$ 254,110	$ 249,870
Liabilities		234,889	234,379
Redeemable non-controlling interest	[1],[2]	$ 87	$ 365
Consolidated Variable Interest Entities
Variable Interest Entity [Line Items]
Number of consolidated real estate joint ventures | joint_venture		1	1
Assets		$ 30	$ 32
Non-consolidated Vairable Interest Entities
Variable Interest Entity [Line Items]
Assets		146,600	160,200
Investment assets		1,200	1,200
Variable interest entity, maximum loss exposure		1,200	1,200
Variable interest entity, unfunded commitments		$ 1,200	$ 1,100
Number of nonconsolidated real estate joint ventures | joint_venture		1	1
Operating income (loss)		$ (5)	$ (5)
AB-Sponsored Investment Funds | Consolidated Variable Interest Entities
Variable Interest Entity [Line Items]
Assets		161	424
Liabilities		6	12
Redeemable non-controlling interest		35	273
AB-Sponsored Investment Funds | VOE Consolidation Model
Variable Interest Entity [Line Items]
Assets		114	188
Liabilities		20	19
Redeemable non-controlling interest		16	52
AB-Sponsored Investment Funds | Non-consolidated Vairable Interest Entities
Variable Interest Entity [Line Items]
Assets		63,500	79,300
Variable interest entity, maximum loss exposure		$ 13	$ 8

[1] See Note 13 for details of Redeemable noncontrolling interest.

[2] See Note 2 for details of balances with variable interest entities.