Primary Components of Net Deferred Tax Asset (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets
Related party interest expense		$ 7
Net operating loss and capital loss carryovers	$ 43	63
Alternative minimum tax and investment tax credits	8	5
Property and equipment	4	4
Investments in domestic affiliates	2	3
Deferred revenue and expenses	42	52
Foreign exchange net losses (AOCI)	12	18
Other	2	2
Total gross deferred tax assets	113	154
Less: Valuation allowance	(22)	(23)
Total deferred tax assets, net of valuation allowance	91	131
Deferred tax liabilities
Property and equipment	(11)	(16)
Investments in domestic and foreign affiliates	(7)	(12)
Other	(2)	(2)
Total gross deferred tax liabilities	(20)	(30)
Net deferred tax assets	$ 71	$ 101