XML 27 R50.htm IDEA: XBRL DOCUMENT v3.2.0.727
Incentive Plans Incentive Plans (Stock-based compensation) (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2015
Jun. 30, 2014
Jun. 30, 2015
Jun. 30, 2014
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Deferred Compensation Arrangement with Individual, Compensation Expense $ 32 $ 33 $ 61 $ 62  
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized 164   $ 164    
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period     3 years    
Restricted Stock Liability Awards [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized 30   $ 30    
Accounts Payable, Current $ 11   $ 11   $ 23