Summary of Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign Currency Transaction Gain (Loss), before Tax	$ (426,000,000)	$ 4,000,000	$ 56,000,000
Revenue Recognition [Abstract]
Average Term Deferred Revenue Is Recognized	P8M
Deferred Revenue	1,500,000,000	1,500,000,000
Number Of Days Interest On Receivables and Revenue On Operating Leases Is Discontinued	time a receivable or account is determined to be uncollectible, at bankruptcy status notification, or greater than 120 days past due
Period For Interest On Receivables and Revenue On Operating Leases Is Discontinued	120 days
Selected Other Costs [Abstract]
Engineering, research, and development	5,500,000,000	5,300,000,000	5,000,000,000
Advertising	4,000,000,000	4,100,000,000	3,900,000,000
Financial Services [Member]
Retail and Lease Supplements [Abstract]
Related Party Transaction Unearned Interest Supplements And Residual Support Revenue From Transactions With Related Party	$ 2,400,000,000	$ 2,800,000,000	$ 3,200,000,000