Business Group Information Schedule of Revenues By Geographic Area Based On The Location of Customers (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Revenues	$ 31,513	$ 32,677	$ 32,466
North America
Segment Reporting Information [Line Items]
Revenues	26,047	27,246	27,623
North America | United States
Segment Reporting Information [Line Items]
Revenues	25,004	26,401	26,488
North America | Canada
Segment Reporting Information [Line Items]
Revenues	878	806	854
North America | Other North America
Segment Reporting Information [Line Items]
Revenues	165	39	281
Europe
Segment Reporting Information [Line Items]
Revenues	3,076	2,957	2,829
Europe | United Kingdom
Segment Reporting Information [Line Items]
Revenues	1,027	857	802
Europe | Switzerland
Segment Reporting Information [Line Items]
Revenues	679	582	648
Europe | Spain
Segment Reporting Information [Line Items]
Revenues	288	405	450
Europe | Other Europe
Segment Reporting Information [Line Items]
Revenues	534	826	900
Asia Pacific
Segment Reporting Information [Line Items]
Revenues	1,417	1,484	1,115
Asia Pacific | China
Segment Reporting Information [Line Items]
Revenues	876	929	578
Asia Pacific | Other Asia Pacific
Segment Reporting Information [Line Items]
Revenues	541	555	537
Africa Middle East
Segment Reporting Information [Line Items]
Revenues	713	672	569
South America
Segment Reporting Information [Line Items]
Revenues	$ 260	$ 318	$ 330