Accumulated Other Comprehensive Income/(Loss) (Details) (USD $) In Millions	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010	Dec. 31, 2009
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	$ 1,001
Net change	963	3,331
Ending Balance	1,964
Accumulated other comprehensive income/(loss) (Numeric) [Abstract]
After-tax gains/(losses) on foreign currency translation	(258)	187
After-tax gains/(losses) on hedges	48	9
After-tax gains/(losses) recognized in income on cash flow hedges	145	53
After-tax gains/(losses) representing the net change in derivative cash flow hedges fair value	(7)	195
Adjustments for New Accounting Pronouncement [Member] | Unrealized gains/(losses) on AFS securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Net change		(144)
Adjustments for New Accounting Pronouncement [Member] | Translation adjustments, net of hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Net change		0
Adjustments for New Accounting Pronouncement [Member] | Cash flow hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Net change		0
Adjustments for New Accounting Pronouncement [Member] | Net loss and prior service costs/(credit) of defined benefit pension and OPEB plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Net change		0
Adjustments for New Accounting Pronouncement [Member] | Accumulated other comprehensive income/(loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Net change		(144)
Cumulative-Effect Adjustment, Consolidation of Variable Interest Entity [Member] | Accumulated other comprehensive income/(loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Net change		129
Accounting Standards Update 2010-11 [Member] | Accumulated other comprehensive income/(loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Net change		15
Accumulated other comprehensive income/(loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	1,001	(91)
Net change	963	3,331
Ending Balance	1,964	3,096
Unrealized gains/(losses) on AFS securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	2,498	2,032
Net change	1,239	2,839
Ending Balance	3,737	4,727
Accumulated other comprehensive income/(loss) (Numeric) [Abstract]
After-tax unrealized losses not related to credit on debt securities	(57)	(97)	(81)	(226)
Translation adjustments, net of hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	253	(16)
Net change	(210)	196
Ending Balance	43	180
Cash flow hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	206	181
Net change	(152)	142
Ending Balance	54	323
Net loss and prior service costs/(credit) of defined benefit pension and OPEB plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance	(1,956)	(2,288)
Net change	86	154
Ending Balance	$ (1,870)	$ (2,134)