Subsequent Events (Narrative) (Details) (USD $) Share data in Millions, except Per Share data	Aug. 03, 2011	Jun. 30, 2011	Dec. 31, 2008
Subsequent Event [Line Items]
Equity method investment book value per share		$ 3.92	$ 10.65
Price per share of Clearwire's stock	$ 2.47	$ 3.78
Excess of carrying value per share compared to closing per share stock price of equity method investment	$ 771,000,000	$ 75,000,000
Sensitivity change in equity method investment closing stock price		$ 0.10
Change in estimated value of equity method investment per $.10 change in equity method investment closing per share stock price		53,200,000
Clearwire Class B Non Voting [Member]
Subsequent Event [Line Items]
Clearwire shares owned		532
Clearwire [Member]
Subsequent Event [Line Items]
Carrying amount of equity method investment including the note receivable		$ 2,300,000,000