FAIR VALUE DISCLOSURES - QUANTITATIVE INFORMATION ABOUT LEVEL 3 (Details) - Level 3 $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Corporate | Matrix pricing model
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Assets, fair value	$ 39	$ 53
Corporate | Market com-parable companies
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Assets, fair value	$ 755	$ 789
Corporate | Minimum | Matrix pricing model
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Spread over the industry-specific benchmark yield curve	0.0075	0
Corporate | Maximum | Matrix pricing model
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Spread over the industry-specific benchmark yield curve	0.0565	565
Corporate | Weighted Average | Matrix pricing model
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Spread over the industry-specific benchmark yield curve	0.0188	125
Separate Accounts assets | Third party appraisal
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Assets, fair value	$ 345	$ 326
Separate Accounts assets | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Assets, fair value	$ 1	$ 1
Spread over the industry-specific benchmark yield curve	0.0228	243
GMIB reinsurance contracts | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Assets, fair value	$ 1,571	$ 10,488
GMIB reinsurance contracts | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.01
Servicing asset, non-performance risk	0.0005	0.0005
GMIB reinsurance contracts | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.063
Servicing asset, non-performance risk	0.0010	0.0010
GMIBNLG | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Liabilities, fair value	$ 4,163	$ 4,149
Servicing liability, non-performance liability	0.010	0.010
GWBL/GMWB | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Liabilities, fair value	$ 77	$ 130
GIB | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Liabilities, fair value	(84)	(27)
GMAB | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Liabilities, fair value	1	5
AB 2016 Acquisition | Alliance Bernstein
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Contingent payment arrangements	$ 11	$ 11
Withdrawal rate | GMIB reinsurance contracts | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.000	0.000
Withdrawal rate | GMIB reinsurance contracts | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.080	0.080
Withdrawal rate | GMIBNLG | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.000	0.000
Withdrawal rate | GMIBNLG | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.124	0.124
Withdrawal rate | GWBL/GMWB | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.000	0.000
Withdrawal rate | GWBL/GMWB | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.070	0.070
Withdrawal rate | GIB | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.00	0.000
Withdrawal rate | GIB | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.07	0.070
EBITDA multiple | Corporate | Minimum | Market com-parable companies
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Equity security, measurement input	4.8	5.3
EBITDA multiple | Corporate | Maximum | Market com-parable companies
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Equity security, measurement input	33.0	27.9
EBITDA multiple | Corporate | Weighted Average | Market com-parable companies
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Equity security, measurement input	13.0	12.9
Long-term revenue growth rate | AB 2016 Acquisition | Alliance Bernstein
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Acquisition-related contingent consideration liability, measurement input	0.310	0.310
Discount rate | Corporate | Minimum | Market com-parable companies
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Equity security, measurement input	0.072	0.072
Discount rate | Corporate | Maximum | Market com-parable companies
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Equity security, measurement input	0.170	0.170
Discount rate | Corporate | Weighted Average | Market com-parable companies
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Equity security, measurement input	0.111	0.111
Discount rate | Separate Accounts assets | Third party appraisal
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.065	0.066
Discount rate | Separate Accounts assets | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.048	0.04409
Discount rate | AB 2016 Acquisition | Alliance Bernstein | Minimum
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Acquisition-related contingent consideration liability, measurement input	0.014	0.014
Discount rate | AB 2016 Acquisition | Alliance Bernstein | Maximum
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Acquisition-related contingent consideration liability, measurement input	0.023	0.023
Cash flow multiples | Corporate | Minimum | Market com-parable companies
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Equity security, measurement input	9.0	9.0
Cash flow multiples | Corporate | Maximum | Market com-parable companies
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Equity security, measurement input	17.7	17.7
Cash flow multiples | Corporate | Weighted Average | Market com-parable companies
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Equity security, measurement input	13.1	13.1
Cap rate | Separate Accounts assets | Third party appraisal
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.045	0.046
Exit capitalization rate | Separate Accounts assets | Third party appraisal
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.056	0.056
Utilization rate | GMIB reinsurance contracts | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.00	0.000
Utilization rate | GMIB reinsurance contracts | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.16	0.160
Utilization rate | GMIBNLG | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.000	0.000
Utilization rate | GMIBNLG | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.160	0.160
Utilization rate | GWBL/GMWB | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	1.00	1.00
Utilization rate | GIB | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.00	0.000
Utilization rate | GIB | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.16	0.160
Equity volatility | GMIB reinsurance contracts | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.09	0.099
Equity volatility | GMIB reinsurance contracts | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.32	0.309
Equity volatility | GMIBNLG | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.200	0.200
Equity volatility | GMIBNLG | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.008	0.008
Equity volatility | GMIBNLG | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.262	0.262
Equity volatility | GWBL/GMWB | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.09	0.099
Equity volatility | GWBL/GMWB | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.32	0.309
Equity volatility | GIB | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.09	0.099
Equity volatility | GIB | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.32	0.309
Equity volatility | GMAB | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.09	0.099
Equity volatility | GMAB | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.32	0.309
Forfeiture rate | GMIBNLG | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.0055	0.0055
Forfeiture rate | GMIBNLG | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.021	0.021
Lapse rate | GMIB reinsurance contracts | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input		0.010
Lapse rate | GMIB reinsurance contracts | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input		0.063
Lapse rate | GWBL/GMWB | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.005	0.009
Lapse rate | GWBL/GMWB | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.057	0.057
Lapse rate | GIB | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.005	0.009
Lapse rate | GIB | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.057	0.057
Lapse rate | GMAB | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.005	0.005
Lapse rate | GMAB | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.110	0.110
Age 0-40 | Measurement Input, Mortality Rate [Member] | GMIB reinsurance contracts | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.0001	0.0001
Age 0-40 | Measurement Input, Mortality Rate [Member] | GMIB reinsurance contracts | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.0018	0.0018
Age 0-40 | Measurement Input, Mortality Rate [Member] | GMIBNLG | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.0001	0.0001
Age 0-40 | Measurement Input, Mortality Rate [Member] | GMIBNLG | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.0019	0.0019
Age 41-60 | Measurement Input, Mortality Rate [Member] | GMIB reinsurance contracts | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.0007	0.0007
Age 41-60 | Measurement Input, Mortality Rate [Member] | GMIB reinsurance contracts | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.0054	0.0054
Age 41-60 | Measurement Input, Mortality Rate [Member] | GMIBNLG | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.0006	0.0006
Age 41-60 | Measurement Input, Mortality Rate [Member] | GMIBNLG | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.0053	0.0053
Age 61-115 | Measurement Input, Mortality Rate [Member] | GMIB reinsurance contracts | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.0042	0.0042
Age 61-115 | Measurement Input, Mortality Rate [Member] | GMIB reinsurance contracts | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing asset, measurement input	0.4200	0.4200
Age 61-115 | Measurement Input, Mortality Rate [Member] | GMIBNLG | Minimum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.0041	0.0041
Age 61-115 | Measurement Input, Mortality Rate [Member] | GMIBNLG | Maximum | Discounted cash flow
Fair Value Inputs Assets Quantitative Information 1 [Line Items]
Servicing liability, measurement input	0.412	0.412