Finance Receivables - Impaired and Non-Accrual Receivables and Troubled Debt Restructurings (Details) (Financial Services [Member], USD $) In Millions, unless otherwise specified	6 Months Ended						6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013 Consumer [Member]	Dec. 31, 2012 Consumer [Member]	Jun. 30, 2012 Consumer [Member]	Jun. 30, 2013 Non-consumer [Member]	Dec. 31, 2012 Non-consumer [Member]	Jun. 30, 2013 Minimum [Member] Finance Receivables [Member] 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		$ 420	$ 422		$ 67	$ 47
Percentage of recorded investment of receivables that were impaired		0.90%	0.90%		0.20%	0.20%
Finance Receivables Non Accrual [Abstract]
Number Of Days At Which Finance Receivables Are Put In Non Accrual Status							120 days
Financing Receivable, Recorded Investment, Nonaccrual Status		265	304		36	29
Financing Receivable, Recorded Investment, Nonaccrual Status, Percentage of Receivable		0.60%	0.60%		0.10%	0.10%
Troubled Debt Restructurings [Abstract]
Financing Receivable, Modifications, Recorded Investment		109		123
Financing Receivable, Modifications, Recorded Investment, Percentage of Receivable		0.20%		0.30%
Financing Receivables, Modifications, Contracts Subsequently Defaulted, Default Rate		6.00%		5.90%
Financing Receivable, Allowance for Credit Losses Related to Consumer Troubled Debt Restructurings		$ 22		$ 17