Accumulated Other Comprehensive Income/(Loss) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance			$ 4,102,000,000
Net change	(3,091,000,000)	(325,000,000)	(3,731,000,000)	1,249,000,000
Net change	(38,000,000)	(189,000,000)	(51,000,000)	(62,000,000)
Net change after tax	(290,000,000)	73,000,000	(352,000,000)	38,000,000
Net change	64,000,000	68,000,000	168,000,000	103,000,000
Total other comprehensive income/(loss), after-tax	(3,355,000,000)	(373,000,000)	(3,966,000,000)	1,328,000,000
Ending Balance	136,000,000		136,000,000
Accumulated other comprehensive income (loss) - supplemental information
After-tax unrealized losses not related to credit on debt securities		(101,000,000)		(101,000,000)
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment Including OTTI, Net of Tax	(3,091,000,000)	(325,000,000)	(3,731,000,000)	1,249,000,000
Net change after tax	(38,000,000)	(189,000,000)	(51,000,000)	(62,000,000)
Net change after tax	(290,000,000)	73,000,000	(352,000,000)	38,000,000
Net change after tax	64,000,000	68,000,000	168,000,000	103,000,000
Total other comprehensive income/(loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	3,491,000,000	2,645,000,000	4,102,000,000	944,000,000
Total other comprehensive income/(loss), after-tax	(3,355,000,000)	(373,000,000)	(3,966,000,000)	1,328,000,000
Ending Balance	136,000,000	2,272,000,000	136,000,000	2,272,000,000
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Total Other comprehensive income/(loss) before tax	(5,481,000,000)	(584,000,000)	(6,458,000,000)	2,186,000,000
Total Other comprehensive income/(loss) tax effect	2,126,000,000	211,000,000	2,492,000,000	(858,000,000)
Unrealized gains/(losses) on AFS securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	6,228,000,000	5,139,000,000	6,868,000,000	3,565,000,000
Net change	(3,091,000,000)	(325,000,000)	(3,731,000,000)	1,249,000,000
Ending Balance	3,137,000,000	4,814,000,000	3,137,000,000	4,814,000,000
Accumulated other comprehensive income (loss) - supplemental information
After-tax unrealized losses not related to credit on debt securities	0		0		0	0	(48,000,000)	(56,000,000)
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Net unrealized gains/(losses) arising during the period before tax	(4,947,000,000)	479,000,000	(5,462,000,000)	3,597,000,000
Net unrealized gains/(losses) arising during the period tax effect	1,931,000,000	(186,000,000)	2,116,000,000	(1,403,000,000)
Net unrealized gains/(losses) arising during the period after tax	(3,016,000,000)	293,000,000	(3,346,000,000)	2,194,000,000
Reclassification adjustment for realized (gains)/losses included in net income before tax	(124,000,000)	(1,014,000,000)	(633,000,000)	(1,550,000,000)
Reclassification adjustment for realized (gains)/losses included in net income tax effect	49,000,000	396,000,000	248,000,000	605,000,000
Reclassification adjustment for realized (gains)/losses included in net income after tax	(75,000,000)	(618,000,000)	(385,000,000)	(945,000,000)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment Including OTTI, Before Tax	(5,071,000,000)	(535,000,000)	(6,095,000,000)	2,047,000,000
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment Including OTTI, Tax	1,980,000,000	210,000,000	2,364,000,000	(798,000,000)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment Including OTTI, Net of Tax	(3,091,000,000)	(325,000,000)	(3,731,000,000)	1,249,000,000
Translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(108,000,000)	101,000,000	(95,000,000)	(26,000,000)
Net change	(38,000,000)	(189,000,000)	(51,000,000)	(62,000,000)
Ending Balance	(146,000,000)	(88,000,000)	(146,000,000)	(88,000,000)
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Translation before tax	(607,000,000)	(765,000,000)	(1,034,000,000)	(305,000,000)
Translation tax effect	223,000,000	282,000,000	381,000,000	113,000,000
Translation after tax	(384,000,000)	(483,000,000)	(653,000,000)	(192,000,000)
Hedges - gain/(loss) before tax	571,000,000	480,000,000	991,000,000	213,000,000
Hedges - gains/(losses) tax effect during period	(225,000,000)	(186,000,000)	(389,000,000)	(83,000,000)
Hedges - gains/(losses) after tax	346,000,000	294,000,000	602,000,000	130,000,000
Net change before tax	(36,000,000)	(285,000,000)	(43,000,000)	(92,000,000)
Net change tax effect	(2,000,000)	96,000,000	(8,000,000)	30,000,000
Net change after tax	(38,000,000)	(189,000,000)	(51,000,000)	(62,000,000)
Cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	58,000,000	16,000,000	120,000,000	51,000,000
Net change after tax	(290,000,000)	73,000,000	(352,000,000)	38,000,000
Ending Balance	(232,000,000)	89,000,000	(232,000,000)	89,000,000
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Net unrealized gains/(losses) before tax	(512,000,000)	128,000,000	(642,000,000)	87,000,000
Net unrealized gains/(losses) arising during the period, tax	201,000,000	(51,000,000)	252,000,000	(34,000,000)
Net unrealized gains/(losses), Net of Tax	(311,000,000)	77,000,000	(390,000,000)	53,000,000
Reclassification adjustment for realized (gains)/losses included in net income, before tax	34,000,000	(5,000,000)	63,000,000	(25,000,000)
Reclassification adjustment for realized (gains)/losses included in net income, tax	(13,000,000)	1,000,000	(25,000,000)	10,000,000
Reclassification adjustment for realized (gains)/losses included in net income, net of tax	21,000,000	(4,000,000)	38,000,000	(15,000,000)
Net change before tax	(478,000,000)	123,000,000	(579,000,000)	62,000,000
Net change tax effect	188,000,000	(50,000,000)	227,000,000	(24,000,000)
Net change after tax	(290,000,000)	73,000,000	(352,000,000)	38,000,000
Net loss and prior service costs/(credit) of defined benefit pension and OPEB plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(2,687,000,000)	(2,611,000,000)	(2,791,000,000)	(2,646,000,000)
Net change	64,000,000	68,000,000	168,000,000	103,000,000
Ending Balance	(2,623,000,000)	(2,543,000,000)	(2,623,000,000)	(2,543,000,000)
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Net gains/(losses), pension and OPEB, arising during period, before tax	37,000,000	32,000,000	85,000,000	34,000,000
Net gains/(losses), pension and OPEB, arising during period, tax	(15,000,000)	(13,000,000)	(25,000,000)	(13,000,000)
Net gains/(losses), pension and OPEB, arising during period, net of tax	22,000,000	19,000,000	60,000,000	21,000,000
Reclassification adjustments included in net income, amortization of net loss, before tax	79,000,000	79,000,000	160,000,000	162,000,000
Reclassification adjustments included in net income, amortization of net loss, tax effect	(31,000,000)	(32,000,000)	(62,000,000)	(64,000,000)
Reclassification adjustments included in net income, amortization of net loss, net of tax	48,000,000	47,000,000	98,000,000	98,000,000
Reclassification adjustments included in net income, prior service costs/(credits), before tax	(11,000,000)	(10,000,000)	(22,000,000)	(21,000,000)
Reclassification adjustments included in net income, prior service costs/(credits), tax	5,000,000	4,000,000	9,000,000	8,000,000
Reclassification adjustments included in net income, prior service costs/(credits), net of tax	(6,000,000)	(6,000,000)	(13,000,000)	(13,000,000)
Other Comprehensive Income (Loss), Foreign Currency Exchange Rate and Other Changes, before Tax	(1,000,000)	12,000,000	36,000,000	(6,000,000)
Other Comprehensive Income (Loss) Foreign Currency Exchange Rate and Other Changes , Tax	1,000,000	(4,000,000)	(13,000,000)	3,000,000
Other Comprehensive Income (Loss), Foreign Currency Exchange Rate and Other Changes, after Tax	0	8,000,000	23,000,000	(3,000,000)
Net change before tax	104,000,000	113,000,000	259,000,000	169,000,000
Net change tax effect	(40,000,000)	(45,000,000)	(91,000,000)	(66,000,000)
Net change after tax	$ 64,000,000	$ 68,000,000	$ 168,000,000	$ 103,000,000