Fair Value Measurements (Summary Of Fair Values, Principal Values And Carrying Values Of Debt Instruments) (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended				6 Months Ended
	Jun. 30, 2012 1.875% Convertible Senior Notes due 2013 [Member]	Jun. 30, 2012 4.0% Convertible Senior Notes due 2014 [Member]	Jun. 30, 2012 8.0% Senior Notes due 2016 [Member]	Jul. 24, 2009 8.0% Senior Notes due 2016 [Member]	Jun. 30, 2012 8.25% Senior Notes due 2019 [Member]	Jul. 24, 2009 8.25% Senior Notes due 2019 [Member]	Jun. 30, 2012 4.254% 2010-1C Tower Securities [Member]	Jun. 30, 2012 5.101% 2010-2C Tower Securities [Member]	Jun. 30, 2012 Fair Value [Member] 1.875% Convertible Senior Notes due 2013 [Member]	Dec. 31, 2011 Fair Value [Member] 1.875% Convertible Senior Notes due 2013 [Member]	Jun. 30, 2012 Fair Value [Member] 4.0% Convertible Senior Notes due 2014 [Member]	Dec. 31, 2011 Fair Value [Member] 4.0% Convertible Senior Notes due 2014 [Member]	Jun. 30, 2012 Fair Value [Member] 8.0% Senior Notes due 2016 [Member]	Dec. 31, 2011 Fair Value [Member] 8.0% Senior Notes due 2016 [Member]	Jun. 30, 2012 Fair Value [Member] 8.25% Senior Notes due 2019 [Member]	Dec. 31, 2011 Fair Value [Member] 8.25% Senior Notes due 2019 [Member]	Jun. 30, 2012 Fair Value [Member] 4.254% 2010-1C Tower Securities [Member]	Dec. 31, 2011 Fair Value [Member] 4.254% 2010-1C Tower Securities [Member]	Jun. 30, 2012 Fair Value [Member] 5.101% 2010-2C Tower Securities [Member]	Dec. 31, 2011 Fair Value [Member] 5.101% 2010-2C Tower Securities [Member]	Jun. 30, 2012 Fair Value [Member] Revolving Credit Facility [Member]	Jun. 30, 2012 Fair Value [Member] 2011 Term Loan [Member]	Dec. 31, 2011 Fair Value [Member] 2011 Term Loan [Member]	Jun. 30, 2012 Fair Value [Member] 2012 Term Loan [Member]	Jun. 30, 2012 Fair Value [Member] Mobilitie Bridge Loan [Member]	Jun. 30, 2012 Principal Value [Member] 1.875% Convertible Senior Notes due 2013 [Member]	Dec. 31, 2011 Principal Value [Member] 1.875% Convertible Senior Notes due 2013 [Member]	Jun. 30, 2012 Principal Value [Member] 4.0% Convertible Senior Notes due 2014 [Member]	Dec. 31, 2011 Principal Value [Member] 4.0% Convertible Senior Notes due 2014 [Member]	Jun. 30, 2012 Principal Value [Member] 8.0% Senior Notes due 2016 [Member]	Dec. 31, 2011 Principal Value [Member] 8.0% Senior Notes due 2016 [Member]	Jun. 30, 2012 Principal Value [Member] 8.25% Senior Notes due 2019 [Member]	Dec. 31, 2011 Principal Value [Member] 8.25% Senior Notes due 2019 [Member]	Jun. 30, 2012 Principal Value [Member] 4.254% 2010-1C Tower Securities [Member]	Dec. 31, 2011 Principal Value [Member] 4.254% 2010-1C Tower Securities [Member]	Jun. 30, 2012 Principal Value [Member] 5.101% 2010-2C Tower Securities [Member]	Dec. 31, 2011 Principal Value [Member] 5.101% 2010-2C Tower Securities [Member]	Jun. 30, 2012 Principal Value [Member] Revolving Credit Facility [Member]	Jun. 30, 2012 Principal Value [Member] 2011 Term Loan [Member]	Dec. 31, 2011 Principal Value [Member] 2011 Term Loan [Member]	Jun. 30, 2012 Principal Value [Member] 2012 Term Loan [Member]	Jun. 30, 2012 Principal Value [Member] Mobilitie Bridge Loan [Member]	Jun. 30, 2012 Carrying Value [Member] 1.875% Convertible Senior Notes due 2013 [Member]	Dec. 31, 2011 Carrying Value [Member] 1.875% Convertible Senior Notes due 2013 [Member]	Jun. 30, 2012 Carrying Value [Member] 4.0% Convertible Senior Notes due 2014 [Member]	Dec. 31, 2011 Carrying Value [Member] 4.0% Convertible Senior Notes due 2014 [Member]	Jun. 30, 2012 Carrying Value [Member] 8.0% Senior Notes due 2016 [Member]	Dec. 31, 2011 Carrying Value [Member] 8.0% Senior Notes due 2016 [Member]	Jun. 30, 2012 Carrying Value [Member] 8.25% Senior Notes due 2019 [Member]	Dec. 31, 2011 Carrying Value [Member] 8.25% Senior Notes due 2019 [Member]	Jun. 30, 2012 Carrying Value [Member] 4.254% 2010-1C Tower Securities [Member]	Dec. 31, 2011 Carrying Value [Member] 4.254% 2010-1C Tower Securities [Member]	Jun. 30, 2012 Carrying Value [Member] 5.101% 2010-2C Tower Securities [Member]	Dec. 31, 2011 Carrying Value [Member] 5.101% 2010-2C Tower Securities [Member]	Jun. 30, 2012 Carrying Value [Member] Revolving Credit Facility [Member]	Jun. 30, 2012 Carrying Value [Member] 2011 Term Loan [Member]	Dec. 31, 2011 Carrying Value [Member] 2011 Term Loan [Member]	Jun. 30, 2012 Carrying Value [Member] 2012 Term Loan [Member]	Jun. 30, 2012 Carrying Value [Member] Mobilitie Bridge Loan [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate for senior notes	1.875%	4.00%	8.00%	8.00%	8.25%	8.25%	4.254%	5.101%
Convertible senior notes, maturity date	2013	2014
Maturity date			2016		2019
Debt instrument									$ 742.6	$ 605.2	$ 966.3	$ 761.6	$ 259.3	$ 405.0	$ 266.9	$ 407.8	$ 710.4	$ 699.0	$ 601.5	$ 579.0	$ 284.0	$ 488.8	$ 494.4	$ 197.5	$ 400.0	$ 535.0	$ 535.0	$ 500.0	$ 500.0	$ 243.8	$ 375.0	$ 243.8	$ 375.0	$ 680.0	$ 680.0	$ 550.0	$ 550.0	$ 284.0	$ 495.0	$ 497.5	$ 200.0	$ 400.0	$ 503.0	$ 485.0	$ 413.6	$ 397.6	$ 242.7	$ 373.2	$ 242.1	$ 372.4	$ 680.0	$ 680.0	$ 550.0	$ 550.0	$ 284.0	$ 493.9	$ 496.3	$ 200.0	$ 400.0