Fair Value Measurements (Narrative) (Details) (USD $)			3 Months Ended	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Level 3 [Member]	Sep. 30, 2013 Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Net unrealized losses related to level 3 financial instruments			$ 200,000	$ 4,800,000
Fair value of senior notes and other long-term debt, including amounts classified as current	$ 4,500,000,000	$ 5,000,000,000