Supplemental Financial Information (Detail) - USD ($) $ in Millions	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Inventories
Finished goods	$ 31		$ 18
Service parts	12		12
Total inventories	43		30
Deferred revenue
Deferred revenue, current	532	$ 395	414
Long-term deferred revenue	72	$ 85	85
Total deferred revenue	$ 604		$ 499