Annual report pursuant to Section 13 and 15(d)

Stock Compensation Plans (Stock Options, Restricted Stock, Deferred Stock Allocation And Performance Share Activity Under Incentive Equity Plans And Nonemployee Directors' Compensation Plans) (Details)

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Stock Compensation Plans (Stock Options, Restricted Stock, Deferred Stock Allocation And Performance Share Activity Under Incentive Equity Plans And Nonemployee Directors' Compensation Plans) (Details) (USD $)
 3 Months Ended 12 Months Ended
Jun. 30, 2011
Mar. 31, 2011
Dec. 31, 2011
Dec. 31, 2009
Stock Options [Member]
Dec. 31, 2011
Restricted Stock [Member]
Dec. 31, 2010
Restricted Stock [Member]
Dec. 31, 2009
Restricted Stock [Member]
Dec. 31, 2011
Performance Awards [Member]
Dec. 31, 2010
Performance Awards [Member]
Dec. 31, 2009
Performance Awards [Member]
Dec. 31, 2011
Other Compensation Costs [Member]
Dec. 31, 2010
Other Compensation Costs [Member]
Dec. 31, 2009
Other Compensation Costs [Member]
Dec. 31, 2011
Employee Stock Ownership Plan E S O P Plan [Member]
Dec. 31, 2011
Directors Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]                              
Options outstanding at beginning of year       2,500                      
Exercised       (2,500)                      
Options outstanding at beginning of year, weighted-average exercise price       $ 5.42                      
Exercised, weighted-average exercise price       $ 5.42                      
Outstanding and restricted at beginning of year   1,217,459 1,217,459   371,712 290,702 315,684 843,238 823,393 594,115 2,509 4,596 2,183    
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period     390,690   125,059 133,666 184,904 263,816 [1] 376,524 [1] 555,046 [1] 1,815 2,075 4,602    
Vested     278,913   (61,330) (50,156) (201,486) (215,870) [2] (343,321) [2] (312,336) [2] (1,713) (4,162) (2,189)    
Forfeited/expired     24,024   (10,275) (2,500) (8,400) (13,749) (13,358) (13,432)          
Outstanding and restricted at end of year     1,305,212   425,166 371,712 290,702 877,435 843,238 823,393 2,611 2,509 4,596    
Vested or expected to vest at December 31, 2011               833,224              
Directors' plans     6,876,060                     6,760,871 115,189
Outstanding, beginning of year   $ 26.03 $ 26.03                        
Granted $ 75.64 $ 77.90 $ 88.60                        
Vested     $ 42.73                        
Forfeited/expired     $ 61.61                        
Outstanding, end of year     $ 43.19                        
[1] The shares granted during the year include 71,956 shares, 114,371 shares and 99,958 shares for each year presented, respectively, related to the 50 percent payout associated with the prior-year pool as actual payout exceeded target.
[2] For each year presented, the shares vested on December 31, 2010, December 31, 2009 and December 31, 2008, respectively, and were valued on February 14, 2011, February 19, 2010 and February 27, 2009, respectively.