DERIVATIVE INSTRUMENTS - Offsetting of Financial Assets and Derivative Assets (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	$ 802		$ 488
Gross amount of liabilities offset in balance sheet	0		0
Net amount of derivative assets presented in balance sheet	802		488
Financial instruments, amount not offset against derivative assets in balance sheet	0		0
Derivative, Collateral, Obligation to Return Cash and Securities	(619)	[1]
Derivative, Collateral, Obligation to Return Cash	(466)		(295)	[2]
Derivative asset, fair value, amount offset against collateral	183		193
Derivative, Collateral, Obligation to Return Securities	(153)
Foreign currency swaps
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	746		445
Gross amount of liabilities offset in balance sheet	0		0
Net amount of derivative assets presented in balance sheet	746		445
Financial instruments, amount not offset against derivative assets in balance sheet	0		0
Derivative, Collateral, Obligation to Return Cash and Securities	(568)
Derivative, Collateral, Obligation to Return Cash			(276)
Derivative asset, fair value, amount offset against collateral	178		169
Foreign currency forwards
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	56		17
Gross amount of liabilities offset in balance sheet	0		0
Net amount of derivative assets presented in balance sheet	56		17
Financial instruments, amount not offset against derivative assets in balance sheet	0		0
Derivative, Collateral, Obligation to Return Cash and Securities	(51)
Derivative, Collateral, Obligation to Return Cash			(16)
Derivative asset, fair value, amount offset against collateral	5		1
Foreign currency options
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets			4
Gross amount of liabilities offset in balance sheet			0
Net amount of derivative assets presented in balance sheet			4
Financial instruments, amount not offset against derivative assets in balance sheet			0
Derivative, Collateral, Obligation to Return Cash			(3)
Derivative asset, fair value, amount offset against collateral			1
Credit default swaps
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets			1
Gross amount of liabilities offset in balance sheet			0
Net amount of derivative assets presented in balance sheet			1
Financial instruments, amount not offset against derivative assets in balance sheet			0
Derivative, Collateral, Obligation to Return Cash			0
Derivative asset, fair value, amount offset against collateral			1
Interest rate swaps
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets			1
Gross amount of liabilities offset in balance sheet			0
Net amount of derivative assets presented in balance sheet			1
Financial instruments, amount not offset against derivative assets in balance sheet			0
Derivative, Collateral, Obligation to Return Cash			0
Derivative asset, fair value, amount offset against collateral			1
Interest rate swaptions
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets			20
Gross amount of liabilities offset in balance sheet			0
Net amount of derivative assets presented in balance sheet			20
Financial instruments, amount not offset against derivative assets in balance sheet			0
Derivative, Collateral, Obligation to Return Cash			0
Derivative asset, fair value, amount offset against collateral			20
Offsetting assets
Offsetting Assets [Line Items]
Gross amounts of recognized financial instruments	2,951		6,144
Gross amounts offset in balance sheet	0		0
Net amounts of financial instruments presented in balance sheet	2,951		6,144
Carrying value of financial instruments not offset in balance sheet	0		0
Collateral not offset in balance sheet	(2,768)		(5,951)
Financial instruments, amount offset against collateral	183		193
Offsetting assets | Securities lending and similar arrangements
Offsetting Assets [Line Items]
Gross amounts of recognized financial instruments	2,149		5,656
Gross amounts offset in balance sheet	0		0
Net amounts of financial instruments presented in balance sheet	2,149		5,656
Carrying value of financial instruments not offset in balance sheet	0		0
Collateral not offset in balance sheet	(2,149)		(5,656)
Financial instruments, amount offset against collateral	$ 0		$ 0

[1] Consists of $153 of pledged securities and $466 of cash.

[2] Consists entirely of cash.