XML 115 R101.htm IDEA: XBRL DOCUMENT v3.8.0.1
Fair Value Measurements (Details) - USD ($)
$ in Millions
Dec. 31, 2017
Dec. 31, 2016
Fair Value Disclosures [Abstract]    
Carrying amount of long-term debt $ 181 $ 201
Fair value of long-term debt $ 200 $ 222