XML 66 R50.htm IDEA: XBRL DOCUMENT v3.8.0.1
Employee Postretirement Benefits (Pension Plans with an ABO in Excess of Plan Assets) (Details) - USD ($)
$ in Millions
Dec. 31, 2017
Dec. 31, 2016
PBO $ 2,146 $ 3,807
ABO 2,134 3,736
Fair value of plan assets $ 1,699 $ 3,243