Fair Value Measurements Nonrecurring Fair Value Changes (Details) (Financial Services [Member], Fair Value, Measurements, Nonrecurring [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Items measured at fair value [Line Items]
Total Gains / (Losses)	$ (12)	$ (12)	$ (25)	$ (27)
North America [Member]
Items measured at fair value [Line Items]
Total Gains / (Losses)	(7)	(7)	(15)	(17)
International [Member]
Items measured at fair value [Line Items]
Total Gains / (Losses)	(5)	(5)	(10)	(10)
Retail [Member] | North America [Member]
Items measured at fair value [Line Items]
Total Gains / (Losses)	(7)	(6)	(15)	(16)
Retail [Member] | International [Member]
Items measured at fair value [Line Items]
Total Gains / (Losses)	(5)	(5)	(10)	(10)
Dealer loans [Member] | North America [Member]
Items measured at fair value [Line Items]
Total Gains / (Losses)	$ 0	$ (1)	$ 0	$ (1)