Fair Value (Schedule Of Fair Value Measurements, Assets, Using Significant Unobservable Inputs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	$ 6,931	$ 7,401	$ 8,691	$ 5,761
Transfers into Level 3, Assets	21	0	136	115
Transfers out of Level 3, Assets	(993)	(1,058)	(5,210)	(3,105)
Recorded in Revenue, Assets	112	91	270	381
Recorded in Other Comprehensive Income, Assets	25	(44)	37	15
Purchases, Assets	1,032	2,416	4,015	6,336
Issuances, Assets	0	0	0	0
Sales, Assets	(45)	(41)	(118)	(44)
Settlements, Assets	(565)	(184)	(1,303)	(878)
Fair Value, ending balance, Assets	6,518	8,581	6,518	8,581
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End	(47)	61	(71)	49
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	6,771	7,192	8,513	5,507
Transfers into Level 3, Assets	21		136	115
Transfers out of Level 3, Assets	(993)	(1,058)	(5,210)	(3,105)
Recorded in Revenue, Assets	181	37	407	391
Recorded in Other Comprehensive Income, Assets	25	(44)	37	15
Purchases, Assets	957	2,239	3,853	6,070
Issuances, Assets
Sales, Assets	(45)	(40)	(118)	(40)
Settlements, Assets	(498)	(67)	(1,199)	(694)
Fair Value, ending balance, Assets	6,419	8,259	6,419	8,259
US Treasury and Federal Agencies, Direct Obligations [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets		17
Transfers out of Level 3, Assets		(17)		(17)
Purchases, Assets		22		39
Fair Value, ending balance, Assets		22		22
US Treasury and Federal Agencies, Mortgage-backed Securities [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	933	932	1,189	673
Transfers into Level 3, Assets			50
Transfers out of Level 3, Assets			(251)	(404)
Recorded in Other Comprehensive Income, Assets	3	2	3	3
Purchases, Assets		590		1,289
Settlements, Assets	(30)	(25)	(85)	(62)
Fair Value, ending balance, Assets	906	1,499	906	1,499
Asset-backed Securities, Student Loans [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	484	1,289	860	1,234
Transfers into Level 3, Assets			0
Transfers out of Level 3, Assets		(379)	(341)	(720)
Recorded in Revenue, Assets	1	(1)	2	2
Recorded in Other Comprehensive Income, Assets	5	(6)	(5)	(6)
Purchases, Assets		0		421
Settlements, Assets	(12)	46	(38)	18
Fair Value, ending balance, Assets	478	949	478	949
Asset-backed Securities, Credit Cards [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	274	79	91	43
Transfers into Level 3, Assets			21
Transfers out of Level 3, Assets	(36)	(20)	(36)	(35)
Recorded in Revenue, Assets	1	2	4	3
Recorded in Other Comprehensive Income, Assets	(1)	0	(5)	(2)
Purchases, Assets		250	224	301
Sales, Assets			(61)
Settlements, Assets	0	0	0	1
Fair Value, ending balance, Assets	238	311	238	311
Asset-backed Securities, Other [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	3,094	2,530	2,798	2,000
Transfers into Level 3, Assets	12		12	114
Transfers out of Level 3, Assets	(11)	0	(11)	(135)
Recorded in Revenue, Assets	10	5	31	22
Recorded in Other Comprehensive Income, Assets	14	(34)	39	14
Purchases, Assets	608	267	1,177	837
Sales, Assets		(37)	(12)	(37)
Settlements, Assets	(267)	2	(574)	(82)
Fair Value, ending balance, Assets	3,460	2,733	3,460	2,733
Asset-backed Securities [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	3,852	3,898	3,749	3,277
Transfers into Level 3, Assets	12		33	114
Transfers out of Level 3, Assets	(47)	(399)	(388)	(890)
Recorded in Revenue, Assets	12	6	37	27
Recorded in Other Comprehensive Income, Assets	18	(40)	29	6
Purchases, Assets	608	517	1,401	1,559
Issuances, Assets
Sales, Assets		(37)	(73)	(37)
Settlements, Assets	(279)	48	(612)	(63)
Fair Value, ending balance, Assets	4,176	3,993	4,176	3,993
Non-US Debt Securities, Mortgage-Backed Securities [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	273	361	1,457	396
Transfers into Level 3, Assets	0			0
Transfers out of Level 3, Assets	(147)	(36)	(1,642)	(739)
Recorded in Revenue, Assets	0	0	0	0
Recorded in Other Comprehensive Income, Assets	0	(1)	3	0
Purchases, Assets	156	608	463	1,261
Issuances, Assets
Sales, Assets		0	0	0
Settlements, Assets	3	(2)	4	12
Fair Value, ending balance, Assets	285	930	285	930
Non-US Debt Securities, Asset-Backed Securities [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	1,362	1,749	1,768	740
Transfers into Level 3, Assets	0			0
Transfers out of Level 3, Assets	(676)	(573)	(2,243)	(693)
Recorded in Revenue, Assets	1	0	1	1
Recorded in Other Comprehensive Income, Assets	4	(3)	4	8
Purchases, Assets	0	286	1,206	1,538
Issuances, Assets
Sales, Assets		(3)	0	(3)
Settlements, Assets	(14)	(50)	(59)	(185)
Fair Value, ending balance, Assets	677	1,406	677	1,406
Non-US Debt Securities, Government Securities [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets				1
Transfers into Level 3, Assets				0
Transfers out of Level 3, Assets				0
Recorded in Revenue, Assets				0
Recorded in Other Comprehensive Income, Assets				0
Purchases, Assets				0
Issuances, Assets
Sales, Assets				0
Settlements, Assets				(1)
Fair Value, ending balance, Assets		0		0
Non-US Debt Securities, Other [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	1	6	71	8
Transfers into Level 3, Assets	0			0
Transfers out of Level 3, Assets		0	(372)	0
Recorded in Revenue, Assets	0	0		0
Recorded in Other Comprehensive Income, Assets	0	0	(3)	0
Purchases, Assets	193	0	500	0
Issuances, Assets
Sales, Assets		0	0	0
Settlements, Assets	0	0	(2)	(2)
Fair Value, ending balance, Assets	194	6	194	6
Non U S Debt Securities [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	1,636	2,116	3,296	1,145
Transfers into Level 3, Assets	0			0
Transfers out of Level 3, Assets	(823)	(609)	4,257	(1,432)
Recorded in Revenue, Assets	1	0	1	1
Recorded in Other Comprehensive Income, Assets	4	(4)	4	8
Purchases, Assets	349	894	2,169	2,799
Issuances, Assets
Sales, Assets		(3)	0	(3)
Settlements, Assets	(11)	(52)	57	(176)
Fair Value, ending balance, Assets	1,156	2,342	1,156	2,342
State And Political Subdivisions [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	49	54	50	50
Transfers into Level 3, Assets			0	1
Transfers out of Level 3, Assets		(2)	0	(3)
Recorded in Revenue, Assets	0	0	0	0
Recorded in Other Comprehensive Income, Assets	(1)	(1)	0	0
Purchases, Assets	0	0	0	3
Sales, Assets		0	0
Settlements, Assets	0	0	(2)	0
Fair Value, ending balance, Assets	48	51	48	51
Collateralized Mortgage Obligations [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	301	173	227	359
Transfers into Level 3, Assets	0		44	0
Transfers out of Level 3, Assets	(123)	(31)	(314)	(359)
Recorded in Revenue, Assets	168	31	369	363
Recorded in Other Comprehensive Income, Assets	1	(1)	1	(2)
Purchases, Assets	0	216	283	381
Sales, Assets	(45)	0	(45)
Settlements, Assets	(178)	(38)	(441)	(392)
Fair Value, ending balance, Assets	124	350	124	350
Other U.S. Debt Securities [Member] | Categories of Investments, Marketable Securities, Available-for-sale Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	0	2	2	3
Transfers into Level 3, Assets	9		9	0
Transfers out of Level 3, Assets	0	0	0	0
Recorded in Revenue, Assets	0	0	0	0
Recorded in Other Comprehensive Income, Assets	0	0	0	0
Purchases, Assets	0	0	0	0
Sales, Assets	0	0	0
Settlements, Assets	0	0	(2)	(1)
Fair Value, ending balance, Assets	9	2	9	2
Foreign Exchange Contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	160	201	168	254
Transfers into Level 3, Assets			0	0
Transfers out of Level 3, Assets		0	0	0
Recorded in Revenue, Assets	(69)	54	(127)	(15)
Recorded in Other Comprehensive Income, Assets	0	0	0	0
Purchases, Assets	75	173	162	256
Sales, Assets	0		0	0
Settlements, Assets	(67)	(117)	(104)	(184)
Fair Value, ending balance, Assets	99	311	99	311
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End	(47)	59	(71)	40
Interest Rate Contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets		8	10	0
Transfers into Level 3, Assets			0	0
Transfers out of Level 3, Assets		0	0	0
Recorded in Revenue, Assets		0	(10)	5
Recorded in Other Comprehensive Income, Assets		0	0	0
Purchases, Assets		4	0	10
Sales, Assets		(1)	0	(4)
Settlements, Assets		0	0	0
Fair Value, ending balance, Assets	0	11	0	11
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End		2	0	9
Derivative Financial Instruments, Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets		209	178	254
Transfers into Level 3, Assets			0
Transfers out of Level 3, Assets		0	0	0
Recorded in Revenue, Assets		54	(137)	(10)
Recorded in Other Comprehensive Income, Assets		0	0	0
Purchases, Assets		177	162	266
Issuances, Assets
Sales, Assets		(1)	0	(4)
Settlements, Assets		(117)	(104)	(184)
Fair Value, ending balance, Assets	99	322	99	322
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End		$ 61	$ (71)	$ 49