v2.4.0.6
Borrowing Arrangements (Details) (USD $)
Dec. 31, 2011
property
Dec. 31, 2010
property
Dec. 31, 2011
Unsecured revolving credit facilities
Dec. 31, 2010
Unsecured revolving credit facilities
Dec. 31, 2011
3 7/8 % Convertible Senior Notes due 2011 upon maturity
Nov. 30, 2011
3 7/8 % Convertible Senior Notes due 2011 upon maturity
Nov. 15, 2011
3 7/8 % Convertible Senior Notes due 2011 upon maturity
Dec. 31, 2010
3 7/8 % Convertible Senior Notes due 2011 upon maturity
Mar. 31, 2010
3 7/8 % Convertible Senior Notes due 2011 upon maturity
Dec. 31, 2011
9% Senior Notes due 2012
Dec. 31, 2010
9% Senior Notes due 2012
Dec. 31, 2009
9% Senior Notes due 2012
Dec. 31, 2011
8 1/4% Senior Notes due 2012
Dec. 31, 2010
8 1/4% Senior Notes due 2012
Dec. 31, 2011
Unsecured term loan due 2013
Dec. 31, 2010
Unsecured term loan due 2013
Dec. 31, 2011
6.25% Senior Notes due 2013
Dec. 31, 2010
6.25% Senior Notes due 2013
Dec. 31, 2011
Unsecured term loan due 2015
Dec. 31, 2010
Unsecured term loan due 2015
Dec. 31, 2011
3.125% Senior Notes due 2015
Dec. 31, 2010
3.125% Senior Notes due 2015
Nov. 30, 2010
3.125% Senior Notes due 2015
Dec. 31, 2011
6% Senior Notes due 2015
Dec. 31, 2010
6% Senior Notes due 2015
Dec. 31, 2011
6 1/2% Senior Notes due 2016
Jul. 31, 2011
6 1/2% Senior Notes due 2016
Dec. 31, 2010
6 1/2% Senior Notes due 2016
Dec. 31, 2011
Unsecured term loan due 2017
Dec. 31, 2010
Unsecured term loan due 2017
Dec. 31, 2011
6 3/4% Senior Notes due 2017
Dec. 31, 2010
6 3/4% Senior Notes due 2017
May 31, 2010
6 3/4% Senior Notes due 2017
Dec. 31, 2009
6 3/4% Senior Notes due 2017
Dec. 31, 2011
4.750% Senior Notes due 2021
May 31, 2011
4.750% Senior Notes due 2021
Dec. 31, 2010
4.750% Senior Notes due 2021
Dec. 31, 2011
6.90% Senior Notes due 2037
Dec. 31, 2010
6.90% Senior Notes due 2037
Dec. 31, 2011
6.59% Senior Notes due 2038
Dec. 31, 2010
6.59% Senior Notes due 2038
Dec. 31, 2011
Mortgage loans and other
Dec. 31, 2010
Mortgage loans and other
Debt instruments                                                                                      
Total $ 6,180,443,000 $ 2,926,954,000 $ 455,578,000 $ 40,000,000 $ 0 $ 230,000,000   $ 230,000,000   $ 82,433,000 $ 82,433,000   $ 72,950,000 $ 0 $ 200,000,000 $ 200,000,000 $ 269,850,000 $ 0 $ 126,875,000 $ 0 $ 400,000,000 $ 400,000,000   $ 234,420,000 $ 0 $ 200,000,000 $ 200,000,000 $ 400,000,000 $ 375,000,000 $ 0 $ 225,000,000 $ 225,000,000     $ 700,000,000   $ 0 $ 52,400,000 $ 0 $ 22,973,000 $ 0 $ 2,762,964,000 $ 1,349,521,000
Interest rate (as a percent)         3.875% 3.875% 3.875% 3.875% 3.875% 9.00% 9.00% 9.00% 8.25% 8.25%     6.25% 6.25%     3.125% 3.125% 3.125% 6.00% 6.00% 6.50% 6.50% 6.50%     6.75% 6.75% 6.75% 6.75% 4.75% 4.75% 4.75% 6.90% 6.90% 6.59% 6.59%    
Capital lease obligations 143,006,000 0                                                                                  
Unamortized fair value adjustment 144,923,000 11,790,000                                                                                  
Unamortized commission fees and discounts (39,256,000) (38,700,000)                                                                                  
Senior notes payable and other debt 6,429,116,000 2,900,044,000                                                                                  
Joint venture partners' share of total debt 46,600,000 4,800,000                                                                                  
Number of properties owned through consolidated joint ventures with mortgage debt 8 3                                                                                  
Debt related to investments in unconsolidated entities $ 131,500,000 $ 45,900,000