Debt and Commitments - Debt Repurchases and Calls (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Debt Repurchases [Abstract]
Gains (Losses) on Extinguishment of Debt	$ (14)	$ (128)	$ (983)
Financial Services [Member]
Debt Repurchases [Abstract]
Gains (Losses) on Extinguishment of Debt	(14)	(68)	(139)
Financial Services [Member] | Unsecured and Asset Backed Debt [Member]
Debt Repurchases [Abstract]
Extinguishment of Debt, Amount	628	2,300	5,600
Disclosed Amount Of Debt Maturing In Reporting Period	43
Gains (Losses) on Extinguishment of Debt	(14)	(68)	(139)
Financial Services [Member] | Unsecured and Asset Backed Debt Maturing 2011 [Member]
Debt Repurchases [Abstract]
Disclosed Amount Of Debt Maturing In Reporting Period		268
Financial Services [Member] | Unsecured and Asset Backed Debt Maturing in 2010 [Member]
Debt Repurchases [Abstract]
Disclosed Amount Of Debt Maturing In Reporting Period			$ 683