Investments (Investee Summarized Income Statement Information) (Details) (Clearwire [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Clearwire [Member]
Revenues	$ 1,265	$ 1,254	$ 535
Equity Method Investment, Summarized Financial Information, Operating Expenses	2,644	3,645	2,698
Equity Method Investment, Summarized Financial Information, Operating Income (Loss)	(1,379)	(2,391)	(2,163)
Net loss before non-controlling interests	(1,744)	(2,856)	(2,251)
Equity Method Investment, Summarized Financial Information, Income (loss) from discontinued operations before non-controlling interests	$ (168)	$ (82)	$ (52)