DERIVATIVE INSTRUMENTS - Offsetting of Financial Assets and Derivative Assets (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	$ 706		$ 802
Gross amount of liabilities offset in balance sheet	0		0
Net amount of derivative assets presented in balance sheet	706		802
Financial instruments, amount not offset against derivative assets in balance sheet	0		0
Derivative, Collateral, Obligation to Return Cash	(552)	[1]	(466)
Derivative, Collateral, Obligation to Return Cash and Securities			(619)	[2]
Derivative asset, fair value, amount offset against collateral	154		183
Derivative, Collateral, Obligation to Return Securities			(153)
Foreign currency swaps
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	637		746
Gross amount of liabilities offset in balance sheet	0		0
Net amount of derivative assets presented in balance sheet	637		746
Financial instruments, amount not offset against derivative assets in balance sheet	0		0
Derivative, Collateral, Obligation to Return Cash	(507)
Derivative, Collateral, Obligation to Return Cash and Securities			(568)
Derivative asset, fair value, amount offset against collateral	130		178
Foreign currency forwards
Offsetting Assets [Line Items]
Gross amount of recognized derivative assets	64		56
Gross amount of liabilities offset in balance sheet	0		0
Net amount of derivative assets presented in balance sheet	64		56
Financial instruments, amount not offset against derivative assets in balance sheet	0		0
Derivative, Collateral, Obligation to Return Cash	(45)
Derivative, Collateral, Obligation to Return Cash and Securities			(51)
Derivative asset, fair value, amount offset against collateral	19		5
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	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	0
Derivative asset, fair value, amount offset against collateral	4
Offsetting assets
Offsetting Assets [Line Items]
Gross amounts of recognized financial instruments	3,264		2,951
Gross amounts offset in balance sheet	0		0
Net amounts of assets presented in balance sheet	3,264		2,951
Carrying value of financial instruments not offset in balance sheet	0		0
Collateral not offset in balance sheet	(3,110)		(2,768)
Financial instruments, amount offset against collateral	154		183
Offsetting assets | Securities lending and similar arrangements
Offsetting Assets [Line Items]
Gross amounts of recognized financial instruments	2,558		2,149
Gross amounts offset in balance sheet	0		0
Net amounts of assets presented in balance sheet	2,558		2,149
Carrying value of financial instruments not offset in balance sheet	0		0
Collateral not offset in balance sheet	(2,558)		(2,149)
Financial instruments, amount offset against collateral	$ 0		$ 0

[1] Consists entirely of cash.

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