DERIVATIVE INSTRUMENTS - Offsetting of Financial Liabilities and Derivative Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	$ (974)	$ (1,852)
Gross amount of assets offset in balance sheet	0	0
Derivative liability, fair value, amount not offset against collateral	(974)	(1,852)
Financial instruments, amount not offset	336	698
Derivative, collateral, right to reclaim securities	527	1,130
Derivative, collateral, right to reclaim cash	23	21
Derivative liability, fair value, amount offset against collateral, subject to master netting agreement	(88)	(3)
Derivative liability, not subject to master netting arrangement	(125)	(146)
Derivative liability, fair value, amount offset against collateral, not subject to master netting agreement	(125)	(146)
Derivative liability, fair value, gross liability including not subject to master netting arrangement	(1,099)	(1,998)
Net amount of derivative liabilities presented in balance sheet	(1,099)	(1,998)
Derivative liability, fair value, amount offset against collateral	(213)	(149)
Foreign currency swaps
Offsetting Liabilities [Line Items]
Net amount of derivative liabilities presented in balance sheet	(224)	(230)
Foreign currency forwards
Offsetting Liabilities [Line Items]
Net amount of derivative liabilities presented in balance sheet	(853)	(1,717)
Foreign currency options
Offsetting Liabilities [Line Items]
Net amount of derivative liabilities presented in balance sheet	(22)	(51)
Offsetting liabilities
Offsetting Liabilities [Line Items]
Gross amounts of recognized financial instruments	(2,581)	(2,524)
Gross amounts offset in balance sheet	0	0
Net amounts of liabilities presented in balance sheet	(2,581)	(2,524)
Carrying value of financial instruments not offset in balance sheet	1,781	1,211
Securities collateral, not offset in balance sheet	527	1,130
Cash collateral, not offset in balance sheet	23	21
Financial instruments, amount offset against collateral	(250)	(162)
Offsetting liabilities | Securities lending and similar arrangements
Offsetting Liabilities [Line Items]
Gross amounts of recognized financial instruments	(1,482)	(526)
Gross amounts offset in balance sheet	0	0
Net amounts of liabilities presented in balance sheet	(1,482)	(526)
Carrying value of financial instruments not offset in balance sheet	1,445	513
Securities collateral, not offset in balance sheet	0	0
Cash collateral, not offset in balance sheet	0	0
Financial instruments, amount offset against collateral	$ (37)	$ (13)