XML 53 R42.htm IDEA: XBRL DOCUMENT v3.10.0.1
General - Devaluation (Details) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2018
Jun. 30, 2017
Jun. 30, 2018
Jun. 30, 2017
Foreign exchange related charges $ 11 $ 0 $ 37 $ 0
Angola, Kwanza        
Foreign exchange related charges $ 11   $ 35