Derivative Financial Instruments and Hedging Activities Counterparty Risk and Collateral (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Derivative [Line Items]
Fair Value of Assets	$ 1,400
Automotive [Member]
Derivative [Line Items]
Fair Value of Assets	560	241
Fair Value of Liabilities	410	610
Fair Value of Assets, Gross derivative amounts not offset in the balance sheet that are eligible for offsetting	(325)	(218)
Fair Value of Liabilities, Gross derivative amounts not offset in the balance sheet that are eligible for offsetting	(325)	(218)
Fair Value of Assets, Net amount	235	23
Fair Value of Liabilities, Net amount	85	392
Derivative asset instruments, adjustment for non-performance risk	2	1
Derivative liability instruments, adjusted for non-performance risk	1	1
Financial Services [Member]
Derivative [Line Items]
Fair Value of Assets	818	1,300
Fair Value of Liabilities	386	381
Fair Value of Assets, Gross derivative amounts not offset in the balance sheet that are eligible for offsetting	(274)	(222)
Fair Value of Liabilities, Gross derivative amounts not offset in the balance sheet that are eligible for offsetting	(274)	(222)
Fair Value of Assets, Net amount	544	1,078
Fair Value of Liabilities, Net amount	112	159
Derivative asset instruments, adjustment for non-performance risk	5	14
Derivative liability instruments, adjusted for non-performance risk	$ 25	$ 5