Fair Value (Schedule of Fair Value Measurements on a Recurring Basis) (Details) (USD $)	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	$ 889,000,000			$ 843,000,000
Investment securities available for sale	99,162,000,000			99,174,000,000
Reduction in assets from netting and the result of cash collateral deposited with derivative counterparties	1,370,000,000		1,930,000,000
Reduction in liabilities from netting and the result of cash collateral received from derivative counterparties	274,000,000		979,000,000
Pricing Methods with Significant Unobservable Market Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure	6,069,000,000			7,564,000,000
Liabilities, fair value disclosure	17,000,000			26,000,000
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	889,000,000			843,000,000
Investment securities available for sale	99,162,000,000			99,174,000,000
Derivative assets	3,469,000,000			5,476,000,000
Other assets	100,000,000			97,000,000
Assets, fair value disclosure	103,620,000,000			105,590,000,000
Derivative instruments, liabilities	4,312,000,000			6,259,000,000
Other liabilities	100,000,000			97,000,000
Liabilities, fair value disclosure	4,412,000,000			6,356,000,000
Recurring | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	3,468,000,000			5,469,000,000
Derivative instruments, liabilities	4,090,000,000			6,013,000,000
Recurring | Interest-rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0			6,000,000
Derivative instruments, liabilities	213,000,000			237,000,000
Recurring | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,000,000			1,000,000
Derivative instruments, liabilities	9,000,000			9,000,000
Recurring | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	20,000,000			20,000,000
Recurring | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	401,000,000			399,000,000
Recurring | US Treasury and federal agencies, direct obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	1,963,000,000			709,000,000
Recurring | US Treasury and federal agencies, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	23,092,000,000			23,563,000,000
Recurring | Total asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	27,552,000,000			29,019,000,000
Recurring | Asset-backed securities, student loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	14,280,000,000			14,542,000,000
Recurring | Asset-backed securities, credit cards
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	7,237,000,000			8,210,000,000
Recurring | Asset-backed securities, sub-prime
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	1,155,000,000			1,203,000,000
Recurring | Asset-backed securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	4,880,000,000			5,064,000,000
Recurring | Total non-U.S. debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	24,866,000,000			24,907,000,000
Recurring | Non-U.S. debt securities, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	11,196,000,000			11,029,000,000
Recurring | Non-U.S. debt securities, asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	4,994,000,000			5,390,000,000
Recurring | Non-US debt securities, government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	3,692,000,000			3,761,000,000
Recurring | Non-U.S. debt securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	4,984,000,000			4,727,000,000
Recurring | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	10,444,000,000			10,263,000,000
Recurring | Collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	5,262,000,000			5,269,000,000
Recurring | Other U.S.debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	468,000,000			424,000,000
Investment securities available for sale	4,946,000,000			4,980,000,000
Recurring | U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	36,000,000			34,000,000
Recurring | Non-U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	1,000,000			1,000,000
Recurring | U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	993,000,000			422,000,000
Recurring | Non-U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	7,000,000			7,000,000
Recurring | Quoted Market Prices in Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	481,000,000			486,000,000
Investment securities available for sale	1,280,000,000			0
Derivative assets	0			0
Other assets	100,000,000			97,000,000
Assets, fair value disclosure	1,861,000,000			583,000,000
Derivative instruments, liabilities	0			0
Other liabilities	100,000,000			97,000,000
Liabilities, fair value disclosure	100,000,000			97,000,000
Recurring | Quoted Market Prices in Active Markets (Level 1) | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0			0
Derivative instruments, liabilities				0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Interest-rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0			0
Derivative instruments, liabilities				0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0			0
Derivative instruments, liabilities				0
Recurring | Quoted Market Prices in Active Markets (Level 1) | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	20,000,000			20,000,000
Recurring | Quoted Market Prices in Active Markets (Level 1) | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	401,000,000			399,000,000
Recurring | Quoted Market Prices in Active Markets (Level 1) | US Treasury and federal agencies, direct obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	1,280,000,000			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | US Treasury and federal agencies, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Total asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Asset-backed securities, student loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Asset-backed securities, credit cards
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Asset-backed securities, sub-prime
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Asset-backed securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Total non-U.S. debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Non-U.S. debt securities, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Non-U.S. debt securities, asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Non-US debt securities, government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Non-U.S. debt securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Other U.S.debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	60,000,000			67,000,000
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Non-U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Quoted Market Prices in Active Markets (Level 1) | Non-U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	408,000,000			357,000,000
Investment securities available for sale	91,819,000,000			91,629,000,000
Derivative assets	8,370,000,000			11,958,000,000
Other assets	0			0
Assets, fair value disclosure	100,597,000,000			103,944,000,000
Derivative instruments, liabilities	8,104,000,000			11,785,000,000
Other liabilities	0			0
Liabilities, fair value disclosure	8,104,000,000			11,785,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	8,312,000,000			11,892,000,000
Derivative instruments, liabilities	7,834,000,000			11,454,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Interest-rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	56,000,000			65,000,000
Derivative instruments, liabilities	269,000,000			331,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	2,000,000			1,000,000
Derivative instruments, liabilities	1,000,000			0
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | US Treasury and federal agencies, direct obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	683,000,000			709,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | US Treasury and federal agencies, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	22,992,000,000			22,847,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Total asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	22,915,000,000			24,040,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Asset-backed securities, student loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	13,947,000,000			14,119,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Asset-backed securities, credit cards
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	7,237,000,000			8,186,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Asset-backed securities, sub-prime
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	1,155,000,000			1,203,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Asset-backed securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	576,000,000			532,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Total non-U.S. debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	23,792,000,000			23,270,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Non-U.S. debt securities, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	11,196,000,000			10,654,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Non-U.S. debt securities, asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	4,382,000,000			4,592,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Non-US debt securities, government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	3,692,000,000			3,761,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Non-U.S. debt securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	4,522,000,000			4,263,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	10,402,000,000			10,220,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	5,060,000,000			5,107,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Other U.S.debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	408,000,000			357,000,000
Investment securities available for sale	4,938,000,000			4,972,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	36,000,000			34,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Non-U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	1,000,000			1,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	993,000,000			422,000,000
Recurring | Pricing Methods with Significant Observable Market Inputs (Level 2) | Non-U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	7,000,000			7,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0
Investment securities available for sale	6,063,000,000			7,545,000,000
Derivative assets	6,000,000			19,000,000
Other assets	0			0
Assets, fair value disclosure	6,069,000,000			7,564,000,000
Derivative instruments, liabilities	17,000,000			26,000,000
Other liabilities	0			0
Liabilities, fair value disclosure	17,000,000			26,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	6,000,000			19,000,000
Derivative instruments, liabilities	8,000,000			17,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Interest-rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0			0
Derivative instruments, liabilities	0			0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0			0
Derivative instruments, liabilities	9,000,000			9,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | US Treasury and federal agencies, direct obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | US Treasury and federal agencies, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	100,000,000			716,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Total asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	4,637,000,000			4,979,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, student loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	333,000,000			423,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, credit cards
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			24,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, sub-prime
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Asset-backed securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	4,304,000,000			4,532,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Total non-U.S. debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	1,074,000,000			1,637,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, mortgage-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			375,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, asset-backed securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	612,000,000			798,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-US debt securities, government securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. debt securities, other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	462,000,000			464,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | State and political subdivisions
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	42,000,000			43,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Collateralized mortgage obligations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	202,000,000			162,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Other U.S.debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading account assets	0
Investment securities available for sale	8,000,000			8,000,000
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. equity securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Pricing Methods with Significant Unobservable Market Inputs (Level 3) | Non-U.S. money-market mutual funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities available for sale	0			0
Recurring | Impact of Netting
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	(4,907,000,000)	[1]		(6,501,000,000)
Other assets	0			0	[2]
Assets, fair value disclosure	(4,907,000,000)	[1]		(6,501,000,000)	[2]
Derivative instruments, liabilities	(3,809,000,000)	[1]		(5,552,000,000)
Other liabilities	0			0	[2]
Liabilities, fair value disclosure	(3,809,000,000)	[1]		(5,552,000,000)	[2]
Recurring | Impact of Netting | Foreign exchange contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	(4,850,000,000)			(6,442,000,000)	[2]
Derivative instruments, liabilities	(3,752,000,000)	[1]		(5,458,000,000)	[2]
Recurring | Impact of Netting | Interest-rate contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	(56,000,000)			(59,000,000)	[2]
Derivative instruments, liabilities	(56,000,000)	[1]		(94,000,000)	[2]
Recurring | Impact of Netting | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	(1,000,000)			0	[2]
Derivative instruments, liabilities	$ (1,000,000)			$ 0	[2]

[1] Represents counterparty netting against level-2 financial assets and liabilities, where a legally enforceable master netting agreement exists between State Street and the counterparty. Netting also reflects asset and liability reductions of $1.37 billion and $274 million, respectively, for cash collateral received from and provided to derivative counterparties.

[2] Represents counterparty netting against level-2 financial assets and liabilities, where a legally enforceable master netting agreement exists between State Street and the counterparty. Netting also reflects asset and liability reductions of $1.93 billion and $979 million, respectively, for cash collateral received from and provided to derivative counterparties.