FAIR VALUE MEASUREMENTS (Details 4) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	$ 3,369,000,000	$ 1,241,000,000	$ 12,743,000,000	$ 7,621,000,000
Sales, assets	(649,000,000)	(277,000,000)	(1,542,000,000)	(681,000,000)
Settlements, assets	(10,244,000,000)	(1,073,000,000)	(14,441,000,000)	(4,053,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	(7,524,000,000)	(109,000,000)	(3,240,000,000)	2,887,000,000
Securities purchased through FRBNY's auction of Maiden Lane III assets	7,100,000,000		7,100,000,000
Transfers into Level 3 at end of reporting period, net gains (losses) not included in realized and unrealized gains and losses related to Level 3 for the period	80,000,000		127,000,000
Transfers out Level 3 at end of reporting period, net gains (losses) not included in realized and unrealized gains and losses related to Level 3 for the period.	29,000,000		83,000,000
Liabilities
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, liabilities	6,000,000	1,000,000	8,000,000	40,000,000
Sales, liabilities	(6,000,000)	(32,000,000)	(20,000,000)	(51,000,000)
Settlements, liabilities	260,000,000	(4,000,000)	753,000,000	273,000,000
Purchases, Sales, Issues and Settlements, Net, liabilities	260,000,000	(35,000,000)	741,000,000	262,000,000
Policyholder contract deposits
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Sales, liabilities	(6,000,000)	(32,000,000)	(20,000,000)	(51,000,000)
Settlements, liabilities	3,000,000	4,000,000	16,000,000	16,000,000
Purchases, Sales, Issues and Settlements, Net, liabilities	(3,000,000)	(28,000,000)	(4,000,000)	(35,000,000)
Derivative liabilities, net
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, liabilities	6,000,000	1,000,000	8,000,000	40,000,000
Settlements, liabilities	196,000,000	6,000,000	540,000,000	15,000,000
Purchases, Sales, Issues and Settlements, Net, liabilities	202,000,000	7,000,000	548,000,000	55,000,000
Other long-term debt
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Settlements, liabilities	61,000,000	(14,000,000)	197,000,000	242,000,000
Purchases, Sales, Issues and Settlements, Net, liabilities	61,000,000	(14,000,000)	197,000,000	242,000,000
Bonds available for sale
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	1,038,000,000	708,000,000	4,737,000,000	6,431,000,000
Sales, assets	(546,000,000)	(27,000,000)	(1,267,000,000)	(70,000,000)
Settlements, assets	(986,000,000)	(745,000,000)	(2,735,000,000)	(2,801,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	(494,000,000)	(64,000,000)	735,000,000	3,560,000,000
Bonds available for sale | Obligations of states, municipalities and political subdivisions
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	189,000,000	78,000,000	394,000,000	254,000,000
Sales, assets	(53,000,000)		(219,000,000)
Settlements, assets	(34,000,000)	(4,000,000)	(36,000,000)	(6,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	102,000,000	74,000,000	139,000,000	248,000,000
Bonds available for sale | Non-U.S. government
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	3,000,000		4,000,000	1,000,000
Sales, assets			(3,000,000)	(1,000,000)
Settlements, assets	(1,000,000)	1,000,000	(1,000,000)	1,000,000
Purchases, Sales, Issues and Settlements, Net, assets	2,000,000	1,000,000		1,000,000
Bonds available for sale | Corporate debt
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	139,000,000	58,000,000	280,000,000	478,000,000
Sales, assets	(6,000,000)	(27,000,000)	(59,000,000)	(27,000,000)
Settlements, assets	(39,000,000)	(87,000,000)	(125,000,000)	(235,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	94,000,000	(56,000,000)	96,000,000	216,000,000
Bonds available for sale | Residential mortgage backed securities (RMBS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	198,000,000	(11,000,000)	2,308,000,000	4,613,000,000
Sales, assets	(360,000,000)		(722,000,000)	(22,000,000)
Settlements, assets	(516,000,000)	(426,000,000)	(1,554,000,000)	(1,085,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	(678,000,000)	(437,000,000)	32,000,000	3,506,000,000
Bonds available for sale | Commercial mortgage-backed securities (CMBS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	299,000,000	178,000,000	1,021,000,000	419,000,000
Sales, assets	(127,000,000)		(260,000,000)	(20,000,000)
Settlements, assets	(57,000,000)	(44,000,000)	(143,000,000)	(193,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	115,000,000	134,000,000	618,000,000	206,000,000
Bonds available for sale | Collateralized Debt Obligations/Asset Backed Securities (CDO/ABS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	210,000,000	405,000,000	730,000,000	666,000,000
Sales, assets			(4,000,000)
Settlements, assets	(339,000,000)	(185,000,000)	(876,000,000)	(1,283,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	(129,000,000)	220,000,000	(150,000,000)	(617,000,000)
Bond trading securities
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	2,202,000,000	377,000,000	7,410,000,000	684,000,000
Sales, assets	(51,000,000)	(183,000,000)	(157,000,000)	(363,000,000)
Settlements, assets	(8,987,000,000)	(174,000,000)	(11,103,000,000)	(390,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	(6,836,000,000)	20,000,000	(3,850,000,000)	(69,000,000)
Bond trading securities | Corporate debt
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Settlements, assets	(1,000,000)	(1,000,000)	(5,000,000)	(10,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	(1,000,000)	(1,000,000)	(5,000,000)	(10,000,000)
Bond trading securities | Residential mortgage backed securities (RMBS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets		197,000,000		300,000,000
Sales, assets	(45,000,000)		(45,000,000)
Settlements, assets	(11,000,000)	(29,000,000)	(49,000,000)	(46,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	(56,000,000)	168,000,000	(94,000,000)	254,000,000
Bond trading securities | Commercial mortgage-backed securities (CMBS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	11,000,000	79,000,000	194,000,000	139,000,000
Sales, assets		(90,000,000)	(106,000,000)	(144,000,000)
Settlements, assets	(10,000,000)	(5,000,000)	(209,000,000)	(87,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	1,000,000	(16,000,000)	(121,000,000)	(92,000,000)
Bond trading securities | Collateralized Debt Obligations/Asset Backed Securities (CDO/ABS)
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	2,191,000,000	101,000,000	7,216,000,000	245,000,000
Sales, assets	(6,000,000)	(93,000,000)	(6,000,000)	(219,000,000)
Settlements, assets	(8,965,000,000)	(139,000,000)	(10,840,000,000)	(247,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	(6,780,000,000)	(131,000,000)	(3,630,000,000)	(221,000,000)
Securities purchased through FRBNY's auction of Maiden Lane III assets	7,100,000,000		7,100,000,000
Equity securities
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets			67,000,000
Sales, assets	(22,000,000)	(8,000,000)	(55,000,000)	(31,000,000)
Settlements, assets	(82,000,000)	(3,000,000)	(80,000,000)	(8,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	(104,000,000)	(11,000,000)	(68,000,000)	(39,000,000)
Other invested assets
Fair value assets and liabilities measured on recurring basis, unobservable input reconciliation
Purchases, assets	129,000,000	156,000,000	529,000,000	506,000,000
Sales, assets	(30,000,000)	(59,000,000)	(63,000,000)	(217,000,000)
Settlements, assets	(189,000,000)	(151,000,000)	(523,000,000)	(854,000,000)
Purchases, Sales, Issues and Settlements, Net, assets	$ (90,000,000)	$ (54,000,000)	$ (57,000,000)	$ (565,000,000)