Debt and Commitments - Debt Instruments Convertible Notes (Details) (USD $)	12 Months Ended						3 Months Ended	12 Months Ended			3 Months Ended	12 Months Ended			3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 Automotive [Member]	Dec. 31, 2011 Automotive [Member]	Dec. 31, 2010 Automotive [Member]	Dec. 31, 2010 Convertible 2016 Notes [Member] Automotive [Member]	Dec. 31, 2012 Convertible 2016 Notes [Member] Automotive [Member]	Dec. 31, 2011 Convertible 2016 Notes [Member] Automotive [Member]	Nov. 03, 2009 Convertible 2016 Notes [Member] Automotive [Member]	Dec. 31, 2010 Convertible 2036 Notes [Member] Automotive [Member]	Dec. 31, 2012 Convertible 2036 Notes [Member] Automotive [Member]	Dec. 31, 2011 Convertible 2036 Notes [Member] Automotive [Member]	Dec. 06, 2006 Convertible 2036 Notes [Member] Automotive [Member]	Dec. 31, 2010 Convertible Notes [Member] Automotive [Member]	Dec. 31, 2012 Convertible Notes [Member] Automotive [Member]	Dec. 31, 2011 Convertible Notes [Member] Automotive [Member]	Dec. 31, 2010 Convertible Notes [Member] Automotive [Member]
Convertible Notes Narrative [Abstract]
Liability component - Principal								$ 883,000,000	$ 883,000,000			$ 25,000,000	$ 25,000,000
Debt Instrument, Interest Rate, Stated Percentage																4.25%
Debt Instrument, Convertible, Conversion Ratio								109.8554				111.0495
Debt Instrument Convertible Principal Used For Conversion Ratio							1,000	1,000			1,000	1,000
Debt Instrument, Convertible, Conversion Price								$ 9.10				$ 9.01
Debt Instrument Convertible Conversion Premium Rate								22.00%				22.00%
Market Price Per Share Common Stock										$ 7.44				$ 7.36
Convertible Note Price To Be Paid Upon Event Percent																100.00%
Increase In Market Price Triggering Option To Terminate Conversion Rights								130.00%				140.00%
Minimum Number of Trading Days								20 days				20 days
Range Of Trading Days								30 days				30 days
Convertible Note Price To Be Paid Upon Redemption Percent												100.00%
Convertible Notes Table Narrative [Abstract]
Liability component - Principal (before underwriter option)								768,000,000	768,000,000
Liability component - Principal (underwriter option)								115,000,000	115,000,000
Liability component - Principal								883,000,000	883,000,000			25,000,000	25,000,000
Liability component - Unamortized discount																(142,000,000)	(172,000,000)
Net carrying amount																766,000,000	736,000,000
Equity component of outstanding debt																(225,000,000)	(225,000,000)
Share value in excess of principal value, if converted																384,000,000	143,000,000
Total effective rate on the liability component								9.20%	9.20%			10.50%	10.50%
Over Allotment Option, percentage								8.60%	8.60%
Share price if convertible notes were converted into shares																$ 12.95	$ 10.76
Interest Cost [Abstract]
Contractual interest coupon																38,000,000	38,000,000	138,000,000
Amortization of discount																30,000,000	27,000,000	87,000,000
Total interest cost on Convertible notes																68,000,000	65,000,000	225,000,000
Conversion Offers [Abstract]
Principal amount of notes converted							2,000,000,000				554,000,000
Convertible note conversion, shares															274,385,596
Cash proceeds from conversion of convertible notes															534,000,000
Convertible note conversion, cash premium per $1000							$ 215				$ 190
Debt Instrument Convertible Principal Used For Conversion Ratio							1,000	1,000			1,000	1,000
Gains (Losses) on Extinguishment of Debt	$ (14,000,000)	$ (128,000,000)	$ (983,000,000)		$ (60,000,000)	$ (844,000,000)									$ (962,000,000)