Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Accounts receivable, allowance for doubtful accounts	$ 285	$ 273
Other intangible assets, accumulated amortization	230	164
Common stock, par value	$ 0	$ 0.01
Common stock, shares authorized	0	1,200,000,000
Common stock, shares issued	809,947,514	807,573,277
Common stock, shares outstanding	749,556,111	765,186,316
Treasury stock, shares	60,391,403	42,386,961
Variable Interest Entity [Line Items]
Non-recourse debt - current, balance at variable interest entities	2,287	2,123
Non-recourse debt - noncurrent, balance at variable interest entities	13,250	13,412
Consolidated Variable Interest Entities [Member]
Variable Interest Entity [Line Items]
Non-recourse debt - current, balance at variable interest entities	238	259
Non-recourse debt - noncurrent, balance at variable interest entities	$ 1,161	$ 1,156