Fair Value Measurements (Narrative) (Details) (USD $)			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net unrealized losses related to level 3 financial instruments			$ 2,500,000
Fair value of senior notes and other long-term debt, including amounts classified as current	$ 4,600,000,000	$ 5,000,000,000