Accumulated Other Comprehensive Income/(Loss) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 4,102
Net change	(640)	1,574
Net change	(13)	127
Net change after tax	(62)	(35)
Net change	104	35
Total other comprehensive income/(loss), after-tax	(611)	1,701
Ending Balance	3,491
Accumulated other comprehensive income (loss) - supplemental information
After-tax unrealized losses not related to credit on debt securities		(48)
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment Including OTTI, Net of Tax	(640)	1,574
Net change after tax	(13)	127
Net change after tax	(62)	(35)
Net change after tax	104	35
Total other comprehensive income/(loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	4,102	944
Total other comprehensive income/(loss), after-tax	(611)	1,701
Ending Balance	3,491	2,645
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Total Other comprehensive income/(loss) before tax	(977)	2,770
Total Other comprehensive income/(loss) tax effect	366	(1,069)
Unrealized gains/(losses) on AFS securities
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	6,868	3,565
Net change	(640)	1,574
Ending Balance	6,228	5,139
Accumulated other comprehensive income (loss) - supplemental information
After-tax unrealized losses not related to credit on debt securities			(56)
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Net unrealized gains/(losses) arising during the period before tax	(515)	3,118
Net unrealized gains/(losses) arising during the period tax effect	185	(1,217)
Net unrealized gains/(losses) arising during the period after tax	(330)	1,901
Reclassification adjustment for realized (gains)/losses included in net income before tax	(509)	(536)
Reclassification adjustment for realized (gains)/losses included in net income tax effect	199	209
Reclassification adjustment for realized (gains)/losses included in net income after tax	310	327
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment Including OTTI, Before Tax	(1,024)	2,582
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment Including OTTI, Tax	384	(1,008)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment Including OTTI, Net of Tax	(640)	1,574
Translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(95)	(26)
Net change	(13)	127
Ending Balance	(108)	101
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Translation before tax	(427)	460
Translation tax effect	158	(169)
Translation after tax	(269)	291
Hedges - gain/(loss) before tax	420	(267)
Hedges - gains/(losses) tax effect during period	(164)	103
Hedges - gains/(losses) after tax	256	(164)
Net change before tax	(7)	193
Net change tax effect	(6)	(66)
Net change after tax	(13)	127
Cash flow hedges
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	120	51
Net change after tax	(62)	(35)
Ending Balance	58	16
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Net unrealized gains/(losses) before tax	(130)	(41)
Net unrealized gains/(losses) arising during the period, tax	51	17
Net unrealized gains/(losses), Net of Tax	(79)	(24)
Reclassification adjustment for realized (gains)/losses included in net income, before tax	29	(20)
Reclassification adjustment for realized (gains)/losses included in net income, tax	(12)	9
Reclassification adjustment for realized (gains)/losses included in net income, net of tax	17	(11)
Net change before tax	(101)	(61)
Net change tax effect	39	26
Net change after tax	(62)	(35)
Net loss and prior service costs/(credit) of defined benefit pension and OPEB plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(2,791)	(2,646)
Net change	104	35
Ending Balance	(2,687)	(2,611)
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Net gains/(losses), pension and OPEB, arising during period, before tax	48	2
Net gains/(losses), pension and OPEB, arising during period, tax	(10)	0
Net gains/(losses), pension and OPEB, arising during period, net of tax	38	2
Reclassification adjustments included in net income, amortization of net loss, before tax	81	83
Reclassification adjustments included in net income, amortization of net loss, tax effect	(31)	(32)
Reclassification adjustments included in net income, amortization of net loss, net of tax	50	51
Reclassification adjustments included in net income, prior service costs/(credits), before tax	(11)	(11)
Reclassification adjustments included in net income, prior service costs/(credits), tax	4	4
Reclassification adjustments included in net income, prior service costs/(credits), net of tax	(7)	(7)
Other Comprehensive Income (Loss), Foreign Currency Exchange Rate and Other Changes, before Tax	37	(18)
Other Comprehensive Income (Loss) Foreign Currency Exchange Rate and Other Changes , Tax	(14)	7
Other Comprehensive Income (Loss), Foreign Currency Exchange Rate and Other Changes, after Tax	23	(11)
Net change before tax	155	56
Net change tax effect	(51)	(21)
Net change after tax	104	35
Net Investment Hedging [Member] | Foreign exchange contract
Changes of the components of Accumulated Other Comprehensive Income (Loss)
Hedges - gain/(loss) before tax	$ 420	$ (267)