Fair Value (Schedule Of Fair Value Measurements, Assets, Using Significant Unobservable Inputs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	$ 8,691	$ 5,761
Transfers into Level 3, Assets	137	115
Transfers out of Level 3, Assets	(5,815)	(4,590)
Recorded in Revenue, Assets	325	437
Recorded in Other Comprehensive Income, Assets	93	(22)
Purchases, Assets	5,334	8,212
Issuances, Assets	0	0
Sales, Assets	(119)	(59)
Settlements, Assets	(1,666)	(1,163)
Fair Value, ending balance, Assets	6,980	8,691
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End	(24)	(59)
Derivative Financial Instruments, Assets [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	178	254
Transfers into Level 3, Assets	0	0
Transfers out of Level 3, Assets	0	0
Recorded in Revenue, Assets	(95)	(124)
Recorded in Other Comprehensive Income, Assets	0	0
Purchases, Assets	137	243
Issuances, Assets
Sales, Assets	0	(7)
Settlements, Assets	(107)	(188)
Fair Value, ending balance, Assets	113	178
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End	(24)	(59)
Foreign exchange contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	168	254
Transfers into Level 3, Assets	0	0
Transfers out of Level 3, Assets	0	0
Recorded in Revenue, Assets	(85)	(134)
Recorded in Other Comprehensive Income, Assets	0	0
Purchases, Assets	137	236
Sales, Assets	0	0
Settlements, Assets	(107)	(188)
Fair Value, ending balance, Assets	113	168
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End	(24)	(68)
Interest rate contracts [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	10	0
Transfers into Level 3, Assets	0	0
Transfers out of Level 3, Assets	0	0
Recorded in Revenue, Assets	(10)	10
Recorded in Other Comprehensive Income, Assets	0	0
Purchases, Assets	0	7
Sales, Assets	0	(7)
Settlements, Assets	0	0
Fair Value, ending balance, Assets	0	10
Change in Unrealized Gains (Losses) Related to Financial Instruments, Assets, Held at Period End	0	9
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	8,513	5,507
Transfers into Level 3, Assets	137	115
Transfers out of Level 3, Assets	(5,815)	(4,590)
Recorded in Revenue, Assets	420	561
Recorded in Other Comprehensive Income, Assets	93	(22)
Purchases, Assets	5,197	7,969
Issuances, Assets
Sales, Assets	(119)	(52)
Settlements, Assets	(1,559)	(975)
Fair Value, ending balance, Assets	6,867	8,513
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | US Treasury and Federal Agencies, Direct Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Transfers out of Level 3, Assets		(40)
Purchases, Assets		40
Fair Value, ending balance, Assets
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | US Treasury and Federal Agencies, Mortgage-backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	1,189	673
Transfers into Level 3, Assets	50
Transfers out of Level 3, Assets	(301)	(936)
Recorded in Other Comprehensive Income, Assets	2	1
Purchases, Assets		1,540
Settlements, Assets	(115)	(89)
Fair Value, ending balance, Assets	825	1,189
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | Asset-backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	3,749	3,277
Transfers into Level 3, Assets	33	114
Transfers out of Level 3, Assets	(523)	(1,315)
Recorded in Revenue, Assets	49	38
Recorded in Other Comprehensive Income, Assets	78	(17)
Purchases, Assets	2,259	1,795
Issuances, Assets
Sales, Assets	(74)	(49)
Settlements, Assets	(922)	(94)
Fair Value, ending balance, Assets	4,649	3,749
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | Asset-backed Securities, Student Loans [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	860	1,234
Transfers into Level 3, Assets	0
Transfers out of Level 3, Assets	(341)	(785)
Recorded in Revenue, Assets	2	3
Recorded in Other Comprehensive Income, Assets	15	(21)
Purchases, Assets	100	421
Settlements, Assets	(48)	8
Fair Value, ending balance, Assets	588	860
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | Asset-backed Securities, Credit Cards [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	91	43
Transfers into Level 3, Assets	21
Transfers out of Level 3, Assets	(136)	(285)
Recorded in Revenue, Assets	6	4
Recorded in Other Comprehensive Income, Assets	(6)	(2)
Purchases, Assets	239	301
Sales, Assets	(62)
Settlements, Assets	(86)	30
Fair Value, ending balance, Assets	67	91
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | Asset-backed Securities, Other [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	2,798	2,000
Transfers into Level 3, Assets	12	114
Transfers out of Level 3, Assets	(46)	(245)
Recorded in Revenue, Assets	41	31
Recorded in Other Comprehensive Income, Assets	69	6
Purchases, Assets	1,920	1,073
Sales, Assets	(12)	(49)
Settlements, Assets	(788)	(132)
Fair Value, ending balance, Assets	3,994	2,798
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | Non U S Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	3,296	1,145
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	(4,677)	(1,777)
Recorded in Revenue, Assets	2	1
Recorded in Other Comprehensive Income, Assets	11	(2)
Purchases, Assets	2,655	4,164
Issuances, Assets
Sales, Assets	0	(3)
Settlements, Assets	(68)	(232)
Fair Value, ending balance, Assets	1,219	3,296
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | Non-US Debt Securities, Mortgage-Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	1,457	396
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	(1,715)	(838)
Recorded in Revenue, Assets		0
Recorded in Other Comprehensive Income, Assets	5	(9)
Purchases, Assets	799	1,920
Sales, Assets	0	0
Settlements, Assets	9	(12)
Fair Value, ending balance, Assets	555	1,457
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | Non-US Debt Securities, Asset-Backed Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	1,768	740
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	(2,493)	(939)
Recorded in Revenue, Assets	2	1
Recorded in Other Comprehensive Income, Assets	8	7
Purchases, Assets	1,317	2,179
Sales, Assets	0	(3)
Settlements, Assets	(78)	(217)
Fair Value, ending balance, Assets	524	1,768
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | Non-US Debt Securities, Government 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
Sales, Assets		0
Settlements, Assets		(1)
Fair Value, ending balance, Assets		0
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | Non-US Debt Securities, Other [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	71	8
Transfers into Level 3, Assets		0
Transfers out of Level 3, Assets	(469)	0
Recorded in Revenue, Assets		0
Recorded in Other Comprehensive Income, Assets	(2)	0
Purchases, Assets	539	65
Sales, Assets	0	0
Settlements, Assets	1	(2)
Fair Value, ending balance, Assets	140	71
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | State And Political Subdivisions [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	50	50
Transfers into Level 3, Assets	0	1
Transfers out of Level 3, Assets	0	(3)
Recorded in Revenue, Assets	0	0
Recorded in Other Comprehensive Income, Assets	(1)	0
Purchases, Assets	0	2
Sales, Assets	0
Settlements, Assets	(1)	0
Fair Value, ending balance, Assets	48	50
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | Collateralized Mortgage Obligations [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	227	359
Transfers into Level 3, Assets	45	0
Transfers out of Level 3, Assets	(314)	(519)
Recorded in Revenue, Assets	369	522
Recorded in Other Comprehensive Income, Assets	3	(4)
Purchases, Assets	283	428
Sales, Assets	(45)
Settlements, Assets	(451)	(559)
Fair Value, ending balance, Assets	117	227
Categories of Investments, Marketable Securities, Available-for-sale Securities [Member] | Other U.S. Debt Securities [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning balance, Assets	2	3
Transfers into Level 3, Assets	9	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
Settlements, Assets	(2)	(1)
Fair Value, ending balance, Assets	$ 9	$ 2