XML 63 R49.htm IDEA: XBRL DOCUMENT v3.7.0.1
Incentive Plans Incentive Plans (Stock-based compensation) (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Deferred Compensation Arrangement with Individual, Compensation Expense $ 27 $ 29 $ 57 $ 53  
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized 137   $ 137    
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 31   $ 31    
Accounts Payable, Current $ 10   $ 10   $ 22