SIGNIFICANT ACCOUNTING POLICIES - OTHER POLICIES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Separate Accounts Disclosure [Abstract]
Gain (loss) recognized on assets transferred to separate account	$ 16,735	$ 8,222	$ (1,148)
Life Insurance Liabilities
Liability For Future Policy Benefits Assumptions [Line Items]
Percentage of life insurance liabilities calculate within traditional life interest rate range	99.10%
Minimum
Liability For Future Policy Benefits Assumptions [Line Items]
Capitalized computer software amortization period	3 years
Minimum | Life Insurance Liabilities
Liability For Future Policy Benefits Assumptions [Line Items]
Liability for future policy benefits, interest rate	5.00%
Minimum | Annuity Liabilities
Liability For Future Policy Benefits Assumptions [Line Items]
Liability for policyholder contract deposits, interest rate	1.60%
Maximum
Liability For Future Policy Benefits Assumptions [Line Items]
Capitalized computer software amortization period	5 years
Maximum | Life Insurance Liabilities
Liability For Future Policy Benefits Assumptions [Line Items]
Liability for future policy benefits, interest rate	6.30%
Maximum | Annuity Liabilities
Liability For Future Policy Benefits Assumptions [Line Items]
Liability for policyholder contract deposits, interest rate	5.50%
Weighted Average | Life Insurance Liabilities
Liability For Future Policy Benefits Assumptions [Line Items]
Liability for future policy benefits, interest rate	5.10%
Weighted Average | Annuity Liabilities
Liability For Future Policy Benefits Assumptions [Line Items]
Liability for policyholder contract deposits, interest rate	4.20%
Investment Management Contracts | Minimum
Liability For Future Policy Benefits Assumptions [Line Items]
Intangible asset useful life	6 years
Investment Management Contracts | Maximum
Liability For Future Policy Benefits Assumptions [Line Items]
Intangible asset useful life	20 years
US
Liability For Future Policy Benefits Assumptions [Line Items]
Amortization period, front-end load commissions	5 years 6 months
Non-US
Liability For Future Policy Benefits Assumptions [Line Items]
Amortization period, front-end load commissions	4 years