Accumulated Other Comprehensive Income/(Loss) (Details) (USD $)	3 Months Ended		9 Months Ended			3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended					3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2012	Sep. 30, 2013 Total other comprehensive income/(loss)	Sep. 30, 2012 Total other comprehensive income/(loss)	Sep. 30, 2013 Total other comprehensive income/(loss)	Sep. 30, 2012 Total other comprehensive income/(loss)	Sep. 30, 2013 Unrealized gains/(losses) on AFS securities	Sep. 30, 2012 Unrealized gains/(losses) on AFS securities	Sep. 30, 2013 Unrealized gains/(losses) on AFS securities	Sep. 30, 2012 Unrealized gains/(losses) on AFS securities	Jun. 30, 2013 Unrealized gains/(losses) on AFS securities	Dec. 31, 2012 Unrealized gains/(losses) on AFS securities	Dec. 31, 2011 Unrealized gains/(losses) on AFS securities	Sep. 30, 2013 Translation adjustments	Sep. 30, 2012 Translation adjustments	Sep. 30, 2013 Translation adjustments	Sep. 30, 2012 Translation adjustments	Sep. 30, 2013 Cash flow hedges	Sep. 30, 2012 Cash flow hedges	Sep. 30, 2013 Cash flow hedges	Sep. 30, 2012 Cash flow hedges	Sep. 30, 2013 Net loss and prior service costs/(credit) of defined benefit pension and OPEB plans	Sep. 30, 2012 Net loss and prior service costs/(credit) of defined benefit pension and OPEB plans	Sep. 30, 2013 Net loss and prior service costs/(credit) of defined benefit pension and OPEB plans	Sep. 30, 2012 Net loss and prior service costs/(credit) of defined benefit pension and OPEB plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance			$ 4,102,000,000			$ 136,000,000	$ 2,272,000,000	$ 4,102,000,000	$ 944,000,000	$ 3,137,000,000	$ 4,814,000,000	$ 6,868,000,000	$ 3,565,000,000				$ (146,000,000)	$ (88,000,000)	$ (95,000,000)	$ (26,000,000)	$ (232,000,000)	$ 89,000,000	$ 120,000,000	$ 51,000,000	$ (2,623,000,000)	$ (2,543,000,000)	$ (2,791,000,000)	$ (2,646,000,000)
Net change	161,000,000	2,083,000,000	(3,570,000,000)	3,332,000,000						161,000,000	2,083,000,000	(3,570,000,000)	3,332,000,000
Net change	4,000,000	13,000,000	(47,000,000)	(49,000,000)													4,000,000	13,000,000	(47,000,000)	(49,000,000)
Net change after tax	69,000,000	23,000,000	(283,000,000)	61,000,000																	69,000,000	23,000,000	(283,000,000)	61,000,000
Net change	20,000,000	35,000,000	188,000,000	138,000,000																					20,000,000	35,000,000	188,000,000	138,000,000
Total other comprehensive income/(loss), after-tax	254,000,000	2,154,000,000	(3,712,000,000)	3,482,000,000		254,000,000	2,154,000,000	(3,712,000,000)	3,482,000,000
Ending Balance	390,000,000		390,000,000			390,000,000	4,426,000,000	390,000,000	4,426,000,000	3,298,000,000	6,897,000,000	3,298,000,000	6,897,000,000				(142,000,000)	(75,000,000)	(142,000,000)	(75,000,000)	(163,000,000)	112,000,000	(163,000,000)	112,000,000	(2,603,000,000)	(2,508,000,000)	(2,603,000,000)	(2,508,000,000)
Accumulated other comprehensive income (loss) - supplemental information
After-tax unrealized losses not related to credit on debt securities		(94,000,000)		(94,000,000)	(101,000,000)					0		0		0	0	(56,000,000)
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Net unrealized gains/(losses) arising during the period before tax										290,000,000	3,872,000,000	(5,172,000,000)	7,469,000,000
Net unrealized gains/(losses) arising during the period tax effect										(113,000,000)	(1,509,000,000)	2,003,000,000	(2,912,000,000)
Net unrealized gains/(losses) arising during the period after tax										177,000,000	2,363,000,000	(3,169,000,000)	4,557,000,000
Reclassification adjustment for realized (gains)/losses included in net income before tax										(26,000,000)	(458,000,000)	(659,000,000)	(2,008,000,000)
Reclassification adjustment for realized (gains)/losses included in net income tax effect										10,000,000	178,000,000	258,000,000	783,000,000
Reclassification adjustment for realized (gains)/losses included in net income after tax										(16,000,000)	(280,000,000)	(401,000,000)	(1,225,000,000)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment Including OTTI, Before Tax										264,000,000	3,414,000,000	(5,831,000,000)	5,461,000,000
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment Including OTTI, Tax										(103,000,000)	(1,331,000,000)	2,261,000,000	(2,129,000,000)
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax	161,000,000	2,083,000,000	(3,570,000,000)	3,332,000,000						161,000,000	2,083,000,000	(3,570,000,000)	3,332,000,000
Translation before tax																	349,000,000	413,000,000	(685,000,000)	108,000,000
Translation tax effect																	(128,000,000)	(153,000,000)	253,000,000	(40,000,000)
Translation after tax																	221,000,000	260,000,000	(432,000,000)	68,000,000
Hedges - gain/(loss) before tax																	(343,000,000)	(404,000,000)	648,000,000	(191,000,000)
Hedges - gains/(losses) tax effect during period																	126,000,000	157,000,000	(263,000,000)	74,000,000
Hedges - gains/(losses) after tax																	(217,000,000)	(247,000,000)	385,000,000	(117,000,000)
Net change before tax																	6,000,000	9,000,000	(37,000,000)	(83,000,000)
Net change tax effect																	(2,000,000)	4,000,000	(10,000,000)	34,000,000
Net change after tax	4,000,000	13,000,000	(47,000,000)	(49,000,000)													4,000,000	13,000,000	(47,000,000)	(49,000,000)
Net unrealized gains/(losses) before tax																					106,000,000	56,000,000	(536,000,000)	143,000,000
Net unrealized gains/(losses) arising during the period, tax																					(42,000,000)	(22,000,000)	210,000,000	(56,000,000)
Net unrealized gains/(losses), Net of Tax																					64,000,000	34,000,000	(326,000,000)	87,000,000
Reclassification adjustment for realized (gains)/losses included in net income, before tax																					7,000,000	(19,000,000)	70,000,000	(44,000,000)
Reclassification adjustment for realized (gains)/losses included in net income, tax																					(2,000,000)	8,000,000	(27,000,000)	18,000,000
Reclassification adjustment for realized (gains)/losses included in net income, net of tax																					5,000,000	(11,000,000)	43,000,000	(26,000,000)
Net change before tax																					113,000,000	37,000,000	(466,000,000)	99,000,000
Net change tax effect																					(44,000,000)	(14,000,000)	183,000,000	(38,000,000)
Net change after tax	69,000,000	23,000,000	(283,000,000)	61,000,000																	69,000,000	23,000,000	(283,000,000)	61,000,000
Net gains/(losses), pension and OPEB, arising during period, before tax																									0	0	85,000,000	34,000,000
Net gains/(losses), pension and OPEB, arising during period, tax																									0	0	(25,000,000)	(13,000,000)
Net gains/(losses), pension and OPEB, arising during period, net of tax																									0	0	60,000,000	21,000,000
Reclassification adjustments included in net income, amortization of net loss, before tax																									80,000,000	81,000,000	240,000,000	243,000,000
Reclassification adjustments included in net income, amortization of net loss, tax effect																									(31,000,000)	(30,000,000)	(93,000,000)	(94,000,000)
Reclassification adjustments included in net income, amortization of net loss, net of tax																									49,000,000	51,000,000	147,000,000	149,000,000
Reclassification adjustments included in net income, prior service costs/(credits), before tax																									(11,000,000)	(11,000,000)	(33,000,000)	(32,000,000)
Reclassification adjustments included in net income, prior service costs/(credits), tax																									4,000,000	4,000,000	13,000,000	12,000,000
Reclassification adjustments included in net income, prior service costs/(credits), net of tax																									(7,000,000)	(7,000,000)	(20,000,000)	(20,000,000)
Other Comprehensive Income (Loss), Foreign Currency Exchange Rate and Other Changes, before Tax																									(35,000,000)	(14,000,000)	1,000,000	(20,000,000)
Other Comprehensive Income (Loss) Foreign Currency Exchange Rate and Other Changes , Tax																									13,000,000	5,000,000	0	8,000,000
Other Comprehensive Income (Loss), Foreign Currency Exchange Rate and Other Changes, after Tax																									(22,000,000)	(9,000,000)	1,000,000	(12,000,000)
Net change before tax																									34,000,000	56,000,000	293,000,000	225,000,000
Net change tax effect																									(14,000,000)	(21,000,000)	(105,000,000)	(87,000,000)
Net change after tax	20,000,000	35,000,000	188,000,000	138,000,000																					20,000,000	35,000,000	188,000,000	138,000,000
Total Other comprehensive income/(loss) before tax						417,000,000	3,516,000,000	(6,041,000,000)	5,702,000,000
Total Other comprehensive income/(loss) tax effect						$ (163,000,000)	$ (1,362,000,000)	$ 2,329,000,000	$ (2,220,000,000)