Fair Value (Schedule Of Fair Value Measurements, Assets, Using Significant Unobservable Inputs) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	$ 6,980,000,000	$ 8,691,000,000
Transfers into Level 3, Assets	0	21,000,000
Transfers out of Level 3, Assets	(424,000,000)	(3,030,000,000)
Recorded in Revenue, Assets	110,000,000	71,000,000
Recorded in Other Comprehensive Income, Assets	32,000,000	15,000,000
Purchases, Assets	463,000,000	1,471,000,000
Issuances, Assets	0	0
Sales, Assets	(36,000,000)	(72,000,000)
Settlements, Assets	(557,000,000)	(347,000,000)
Fair Value, ending balance, Assets	6,568,000,000	6,820,000,000
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End	53,000,000	(47,000,000)
Derivative instruments, assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	113,000,000	178,000,000
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	0	0
Recorded in Revenue, Assets	95,000,000	(75,000,000)
Recorded in Other Comprehensive Income, Assets	0	0
Purchases, Assets	53,000,000	110,000,000
Sales, Assets	0	1,000,000
Settlements, Assets	(89,000,000)	(87,000,000)
Fair Value, ending balance, Assets	172,000,000	127,000,000
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End	53,000,000	(47,000,000)
Foreign exchange contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	113,000,000	168,000,000
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	0	0
Recorded in Revenue, Assets	95,000,000	(65,000,000)
Recorded in Other Comprehensive Income, Assets	0	0
Purchases, Assets	53,000,000	110,000,000
Sales, Assets	0	0
Settlements, Assets	(89,000,000)	(86,000,000)
Fair Value, ending balance, Assets	172,000,000	127,000,000
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End	53,000,000	(47,000,000)
Interest-rate contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets		10,000,000
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets		0
Recorded in Revenue, Assets		(10,000,000)
Recorded in Other Comprehensive Income, Assets		0
Purchases, Assets		0
Sales, Assets		1,000,000
Settlements, Assets		(1,000,000)
Fair Value, ending balance, Assets		0
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End		0
Categories of investments, marketable securities, available-for-sale securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	6,867,000,000	8,513,000,000
Transfers into Level 3, Assets		21,000,000
Transfers out of Level 3, Assets	(424,000,000)	(3,030,000,000)
Recorded in Revenue, Assets	15,000,000	146,000,000
Recorded in Other Comprehensive Income, Assets	32,000,000	15,000,000
Purchases, Assets	410,000,000	1,361,000,000
Sales, Assets	(36,000,000)	(73,000,000)
Settlements, Assets	(468,000,000)	(260,000,000)
Fair Value, ending balance, Assets	6,396,000,000	6,693,000,000
Categories of investments, marketable securities, available-for-sale securities | US Treasury and federal agencies, mortgage-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	825,000,000	1,189,000,000
Transfers into Level 3, Assets
Transfers out of Level 3, Assets		(251,000,000)
Recorded in Other Comprehensive Income, Assets
Settlements, Assets	(27,000,000)	(26,000,000)
Fair Value, ending balance, Assets	798,000,000	912,000,000
Categories of investments, marketable securities, available-for-sale securities | Total asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	4,649,000,000	3,749,000,000
Transfers into Level 3, Assets		21,000,000
Transfers out of Level 3, Assets	(100,000,000)	(341,000,000)
Recorded in Revenue, Assets	13,000,000	12,000,000
Recorded in Other Comprehensive Income, Assets	28,000,000	14,000,000
Purchases, Assets	180,000,000	422,000,000
Sales, Assets	(36,000,000)	(73,000,000)
Settlements, Assets	(377,000,000)	(84,000,000)
Fair Value, ending balance, Assets	4,357,000,000	3,720,000,000
Categories of investments, marketable securities, available-for-sale securities | Asset-backed securities, student loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	588,000,000	860,000,000
Transfers into Level 3, Assets
Transfers out of Level 3, Assets	(100,000,000)	(341,000,000)
Recorded in Revenue, Assets		1,000,000
Recorded in Other Comprehensive Income, Assets	7,000,000	(2,000,000)
Purchases, Assets
Sales, Assets	(26,000,000)
Settlements, Assets	(8,000,000)	(7,000,000)
Fair Value, ending balance, Assets	461,000,000	511,000,000
Categories of investments, marketable securities, available-for-sale securities | Asset-backed securities, credit cards
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	67,000,000	91,000,000
Transfers into Level 3, Assets		21,000,000
Transfers out of Level 3, Assets	0	0
Recorded in Revenue, Assets		1,000,000
Recorded in Other Comprehensive Income, Assets	0	0
Purchases, Assets		67,000,000
Sales, Assets	0	(61,000,000)
Settlements, Assets	(43,000,000)	0
Fair Value, ending balance, Assets	24,000,000	119,000,000
Categories of investments, marketable securities, available-for-sale securities | Asset-backed securities, other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	3,994,000,000	2,798,000,000
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	0	0
Recorded in Revenue, Assets	13,000,000	10,000,000
Recorded in Other Comprehensive Income, Assets	21,000,000	16,000,000
Purchases, Assets	180,000,000	355,000,000
Sales, Assets	(10,000,000)	(12,000,000)
Settlements, Assets	(326,000,000)	(77,000,000)
Fair Value, ending balance, Assets	3,872,000,000	3,090,000,000
Categories of investments, marketable securities, available-for-sale securities | Total non-U.S. debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	1,219,000,000	3,296,000,000
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	(324,000,000)	(2,306,000,000)
Recorded in Revenue, Assets	2,000,000	0
Recorded in Other Comprehensive Income, Assets	3,000,000	0
Purchases, Assets	230,000,000	833,000,000
Sales, Assets	0	0
Settlements, Assets	(53,000,000)	(5,000,000)
Fair Value, ending balance, Assets	1,077,000,000	1,818,000,000
Categories of investments, marketable securities, available-for-sale securities | Non-U.S. debt securities, mortgage-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	555,000,000	1,457,000,000
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	(207,000,000)	(1,157,000,000)
Recorded in Revenue, Assets		0
Recorded in Other Comprehensive Income, Assets	0	1,000,000
Purchases, Assets	0	159,000,000
Sales, Assets	0	0
Settlements, Assets	(17,000,000)	9,000,000
Fair Value, ending balance, Assets	331,000,000	469,000,000
Categories of investments, marketable securities, available-for-sale securities | Non-U.S. debt securities, asset-backed securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	524,000,000	1,768,000,000
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	(77,000,000)	(1,084,000,000)
Recorded in Revenue, Assets	2,000,000	0
Recorded in Other Comprehensive Income, Assets	3,000,000	(1,000,000)
Purchases, Assets	51,000,000	366,000,000
Sales, Assets	0	0
Settlements, Assets	(33,000,000)	(14,000,000)
Fair Value, ending balance, Assets	470,000,000	1,035,000,000
Categories of investments, marketable securities, available-for-sale securities | Non-U.S. debt securities, other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	140,000,000	71,000,000
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	(40,000,000)	(65,000,000)
Recorded in Revenue, Assets		0
Recorded in Other Comprehensive Income, Assets	0	0
Purchases, Assets	179,000,000	308,000,000
Sales, Assets	0	0
Settlements, Assets	(3,000,000)	0
Fair Value, ending balance, Assets	276,000,000	314,000,000
Categories of investments, marketable securities, available-for-sale securities | State and political subdivisions
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	48,000,000	50,000,000
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	0	0
Recorded in Revenue, Assets	0	0
Recorded in Other Comprehensive Income, Assets	1,000,000	1,000,000
Purchases, Assets	0	0
Sales, Assets	0
Settlements, Assets	(2,000,000)	(1,000,000)
Fair Value, ending balance, Assets	47,000,000	50,000,000
Categories of investments, marketable securities, available-for-sale securities | Collateralized mortgage obligations
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	117,000,000	227,000,000
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	0	(132,000,000)
Recorded in Revenue, Assets	0	134,000,000
Recorded in Other Comprehensive Income, Assets	0	0
Purchases, Assets	0	106,000,000
Sales, Assets	0	0
Settlements, Assets	(9,000,000)	(142,000,000)
Fair Value, ending balance, Assets	108,000,000	193,000,000
Categories of investments, marketable securities, available-for-sale securities | Other U.S.debt securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	9,000,000	2,000,000
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	0	0
Recorded in Revenue, Assets	0	0
Recorded in Other Comprehensive Income, Assets	0	0
Purchases, Assets	0	0
Sales, Assets	0	0
Settlements, Assets	0	(2,000,000)
Fair Value, ending balance, Assets	$ 9,000,000	$ 0