XML 141 R120.htm IDEA: XBRL DOCUMENT v3.3.1.900
Compensation Plans (Stock Options) (Narrative) (Details) - USD ($)
$ / shares in Units, $ in Millions
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Realized tax benefit from stock options exercised $ 42 $ 45 $ 39
Stock Options Granted Between 2004 and 2008 [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Option term 6 years    
Vesting period 3 years    
Stock Options Granted Prior to 2004 [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Option term 10 years    
Stock Options Granted Between 2009 and 2014 [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Option term 7 years    
Stock Options [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Requisite service period for retirement eligible employees 6 months    
Weighted-average grant date fair value of options granted $ 11.57 $ 13.68 $ 10.40
Total intrinsic value of options exercised $ 160 $ 219 $ 230
Realized tax benefit from stock options exercised 51    
Unrecognized stock-based compensation expense $ 32    
Unrecognized stock-based compensation expense, weighted-average recognition period, in years 1 year 6 months 27 days