XML 63 R52.htm IDEA: XBRL DOCUMENT v3.8.0.1
Deferred Revenue - Additional Information (Detail) - USD ($)
$ in Millions
Sep. 30, 2017
Dec. 31, 2016
Sep. 30, 2016
Deferred Revenue Arrangement [Line Items]      
Deferred revenue current liabilities $ 33 $ 27 $ 24
Deferred revenue non-current liabilities 75 $ 66 61
ETC      
Deferred Revenue Arrangement [Line Items]      
Deferred revenue current liabilities 29   24
Deferred revenue non-current liabilities $ 70   $ 61