Stock-Based Compensation - Net Change in Amounts Capitalized or Accrued (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Other assets	$ (269)	$ (174)	$ 62
Deferred Compensation, Share-based Payments
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Accrued expenses (accrued warranty expenses)	(1)	(2)
Other assets	$ 2	$ 8