Fair Value Measurements (Summary Of Fair Values, Principal Values And Carrying Values Of The Company Debt Instruments) (Details) (USD $) In Millions, unless otherwise specified																																																				6 Months Ended
	Jun. 30, 2011	Jun. 30, 2011 Fair Value [Member] 1.875 % Convertible Senior Notes Due 2013 [Member]	Dec. 31, 2010 Fair Value [Member] 1.875 % Convertible Senior Notes Due 2013 [Member]	Jun. 30, 2011 Fair Value [Member] 4.0 % Convertible Senior Notes Due 2014 [Member]	Dec. 31, 2010 Fair Value [Member] 4.0 % Convertible Senior Notes Due 2014 [Member]	Jun. 30, 2011 Fair Value [Member] 8.0 % Senior Notes Due 2016 [Member]	Dec. 31, 2010 Fair Value [Member] 8.0 % Senior Notes Due 2016 [Member]	Jun. 30, 2011 Fair Value [Member] 8.25 % Senior Notes Due 2019 [Member]	Dec. 31, 2010 Fair Value [Member] 8.25 % Senior Notes Due 2019 [Member]	Jun. 30, 2011 Fair Value [Member] 4.254% Secured Tower Revenue Securities Series 2010-1 [Member]	Dec. 31, 2010 Fair Value [Member] 4.254% Secured Tower Revenue Securities Series 2010-1 [Member]	Jun. 30, 2011 Fair Value [Member] 5.101% Secured Tower Revenue Securities Series 2010-2 [Member]	Dec. 31, 2010 Fair Value [Member] 5.101% Secured Tower Revenue Securities Series 2010-2 [Member]	Jun. 30, 2011 Fair Value [Member] Revolving Credit Facility [Member]	Dec. 31, 2010 Fair Value [Member] Revolving Credit Facility [Member]	Jun. 30, 2011 Fair Value [Member] Term Loan [Member]	Dec. 31, 2010 Fair Value [Member] Term Loan [Member]	Jun. 30, 2011 Principal Value [Member] 1.875 % Convertible Senior Notes Due 2013 [Member]	Dec. 31, 2010 Principal Value [Member] 1.875 % Convertible Senior Notes Due 2013 [Member]	Jun. 30, 2011 Principal Value [Member] 4.0 % Convertible Senior Notes Due 2014 [Member]	Dec. 31, 2010 Principal Value [Member] 4.0 % Convertible Senior Notes Due 2014 [Member]	Jun. 30, 2011 Principal Value [Member] 8.0 % Senior Notes Due 2016 [Member]	Dec. 31, 2010 Principal Value [Member] 8.0 % Senior Notes Due 2016 [Member]	Jun. 30, 2011 Principal Value [Member] 8.25 % Senior Notes Due 2019 [Member]	Dec. 31, 2010 Principal Value [Member] 8.25 % Senior Notes Due 2019 [Member]	Jun. 30, 2011 Principal Value [Member] 4.254% Secured Tower Revenue Securities Series 2010-1 [Member]	Dec. 31, 2010 Principal Value [Member] 4.254% Secured Tower Revenue Securities Series 2010-1 [Member]	Jun. 30, 2011 Principal Value [Member] 5.101% Secured Tower Revenue Securities Series 2010-2 [Member]	Dec. 31, 2010 Principal Value [Member] 5.101% Secured Tower Revenue Securities Series 2010-2 [Member]	Jun. 30, 2011 Principal Value [Member] Revolving Credit Facility [Member]	Dec. 31, 2010 Principal Value [Member] Revolving Credit Facility [Member]	Jun. 30, 2011 Principal Value [Member] Term Loan [Member]	Dec. 31, 2010 Principal Value [Member] Term Loan [Member]	Jun. 30, 2011 Carrying Value [Member] 1.875 % Convertible Senior Notes Due 2013 [Member]	Dec. 31, 2010 Carrying Value [Member] 1.875 % Convertible Senior Notes Due 2013 [Member]	Jun. 30, 2011 Carrying Value [Member] 4.0 % Convertible Senior Notes Due 2014 [Member]	Dec. 31, 2010 Carrying Value [Member] 4.0 % Convertible Senior Notes Due 2014 [Member]	Jun. 30, 2011 Carrying Value [Member] 8.0 % Senior Notes Due 2016 [Member]	Dec. 31, 2010 Carrying Value [Member] 8.0 % Senior Notes Due 2016 [Member]	Jun. 30, 2011 Carrying Value [Member] 8.25 % Senior Notes Due 2019 [Member]	Dec. 31, 2010 Carrying Value [Member] 8.25 % Senior Notes Due 2019 [Member]	Jun. 30, 2011 Carrying Value [Member] 4.254% Secured Tower Revenue Securities Series 2010-1 [Member]	Dec. 31, 2010 Carrying Value [Member] 4.254% Secured Tower Revenue Securities Series 2010-1 [Member]	Jun. 30, 2011 Carrying Value [Member] 5.101% Secured Tower Revenue Securities Series 2010-2 [Member]	Dec. 31, 2010 Carrying Value [Member] 5.101% Secured Tower Revenue Securities Series 2010-2 [Member]	Jun. 30, 2011 Carrying Value [Member] Revolving Credit Facility [Member]	Dec. 31, 2010 Carrying Value [Member] Revolving Credit Facility [Member]	Jun. 30, 2011 Carrying Value [Member] Term Loan [Member]	Dec. 31, 2010 Carrying Value [Member] Term Loan [Member]	Jun. 30, 2011 1.875 % Convertible Senior Notes Due 2013 [Member]	Jun. 30, 2011 4.0 % Convertible Senior Notes Due 2014 [Member]	Jun. 30, 2011 8.0 % Senior Notes Due 2016 [Member]	Jun. 30, 2011 8.25 % Senior Notes Due 2019 [Member]	Jun. 30, 2011 4.254% Secured Tower Revenue Securities Series 2010-1 [Member]	Jun. 30, 2011 5.101% Secured Tower Revenue Securities Series 2010-2 [Member]
Debt instrument		$ 590.2	$ 617.4	$ 703.1	$ 744.4	$ 398.4	$ 405.9	$ 401.3	$ 409.7	$ 702.1	$ 691.9	$ 569.3	$ 556.9		$ 20.0	$ 500.0		$ 535.0	$ 550.0	$ 500.0	$ 500.0	$ 375.0	$ 375.0	$ 375.0	$ 375.0	$ 680.0	$ 680.0	$ 550.0	$ 550.0		$ 20.0	$ 500.0		$ 467.8	$ 464.0	$ 382.6	$ 368.5	$ 373.0	$ 372.9	$ 372.2	$ 372.1	$ 680.0	$ 680.0	$ 550.0	$ 550.0		$ 20.0	$ 498.8
Interest rates for senior notes	1.85%																																																	1.875%	4.00%	8.00%	8.25%	4.254%	5.101%
Convertible senior notes, maturity date																																																		2013	2014
Maturity date																																																				2016	2019