DERIVATIVE INSTRUMENTS - Offsetting of Financial Liabilities and Derivative Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2015		Dec. 31, 2014
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	$ (384)		$ (2,423)
Gross amount of assets offset in balance sheet	0		0
Net amount of derivative liabilities presented in balance sheet	(384)		(2,423)
Financial instruments, amount not offset against derivative liabilities in balance sheet	0		0
Derivative, Collateral, Right to Reclaim Securities	7	[1]	1,621	[2]
Derivative Liability, Fair Value, Amount Offset Against Collateral	(377)		(802)
Foreign currency swaps
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	(352)		(318)
Gross amount of assets offset in balance sheet	0		0
Net amount of derivative liabilities presented in balance sheet	(352)		(318)
Financial instruments, amount not offset against derivative liabilities in balance sheet	0		0
Derivative, Collateral, Right to Reclaim Securities	0		0
Derivative Liability, Fair Value, Amount Offset Against Collateral	(352)		(318)
Foreign currency forwards
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	(24)		(1,912)
Gross amount of assets offset in balance sheet	0		0
Net amount of derivative liabilities presented in balance sheet	(24)		(1,912)
Financial instruments, amount not offset against derivative liabilities in balance sheet	0		0
Derivative, Collateral, Right to Reclaim Securities	5		1,439
Derivative Liability, Fair Value, Amount Offset Against Collateral	(19)		(473)
Foreign currency options
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities	(8)		(33)
Gross amount of assets offset in balance sheet	0		0
Net amount of derivative liabilities presented in balance sheet	(8)		(33)
Financial instruments, amount not offset against derivative liabilities in balance sheet	0		0
Derivative, Collateral, Right to Reclaim Securities	2		24
Derivative Liability, Fair Value, Amount Offset Against Collateral	(6)		(9)
Interest rate swaptions
Offsetting Liabilities [Line Items]
Gross amount of recognized derivative liabilities			(160)
Gross amount of assets offset in balance sheet			0
Net amount of derivative liabilities presented in balance sheet			(160)
Financial instruments, amount not offset against derivative liabilities in balance sheet			0
Derivative, Collateral, Right to Reclaim Securities			158
Derivative Liability, Fair Value, Amount Offset Against Collateral			(2)
Offsetting liabilities
Offsetting Liabilities [Line Items]
Gross amounts of recognized financial instruments	(1,291)		(4,616)
Gross amounts offset in balance sheet	0		0
Net amounts of liabilities presented in balance sheet	(1,291)		(4,616)
Carrying value of financial instruments not offset in balance sheet	885		2,149
Collateral not offset in balance sheet	7		1,621
Financial instruments, amount offset against collateral	(399)		(846)
Offsetting liabilities | Securities lending and similar arrangements
Offsetting Liabilities [Line Items]
Gross amounts of recognized financial instruments	(907)		(2,193)
Gross amounts offset in balance sheet	0		0
Net amounts of liabilities presented in balance sheet	(907)		(2,193)
Carrying value of financial instruments not offset in balance sheet	885		2,149
Collateral not offset in balance sheet	0		0
Financial instruments, amount offset against collateral	$ (22)		$ (44)

[1] Consists entirely of cash.

[2] Consists entirely of pledged securities