Finance Receivables - Impaired and Troubled Debt Restructurings (Details) (Financial Services [Member], USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012 Consumer [Member]	Dec. 31, 2011 Consumer [Member]	Sep. 30, 2011 Consumer [Member]	Sep. 30, 2012 Non-consumer [Member]	Dec. 31, 2011 Non-consumer [Member]
Financing Receivable Impaired [Abstract]
Number of Days Past Due After Which Consumer Receivables are Considered Impaired	greater than 120 days past due
Recorded investment of receivables that were impaired		$ 411	$ 382		$ 61	$ 64
Percentage of recorded investment of receivables that were impaired		0.90%	0.80%		0.20%	0.20%
Troubled Debt Restructurings [Abstract]
Financing Receivable, Modifications, Recorded Investment		185		297
Financing Receivable, Modifications, Recorded Investment, Percentage of Receivable		0.40%		0.60%
Financing Receivables, Modifications, Contracts Subsequently Defaulted, Default Rate		5.70%
Financing Receivable, Allowance for Credit Losses Related to Consumer Troubled Debt Restructurings		$ 18		$ 13