Other Comprehensive (Loss) Income - Components of Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Components of AOCI
Net	$ (9)	$ (9)	$ (10)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(17)	(3)	(2)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	(29)	1	3
Tax (expense) benefit	6	2	0
Other comprehensive income/(loss)	(40)	0	1
Net	(49)	(9)	(9)
Unrealized losses) gains on sales hedging
Components of AOCI
Net	5	(2)	(2)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	7	8	(3)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	(15)	1	3
Tax (expense) benefit	2	(2)	0
Other comprehensive income/(loss)	(6)	7	0
Net	(1)	5	(2)
Unrealized (losses)/ gains on forward interest rate swaps
Components of AOCI
Net	(8)	0	0
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(12)	(12)	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	1	0	0
Tax (expense) benefit	4	4	0
Other comprehensive income/(loss)	(7)	(8)	0
Net	(15)	(8)	0
Unrealized gains (losses) on investments
Components of AOCI
Net	0	0	0
Other Comprehensive Income (Loss), before Reclassifications, before Tax	0	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	0	0	0
Tax (expense) benefit	0	0	0
Other comprehensive income/(loss)	0	0	0
Net	0	0	0
Currency Translation Adjustments
Components of AOCI
Net	(6)	(7)	(8)
Other Comprehensive Income (Loss), before Reclassifications, before Tax	(12)	1	1
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	(15)	0	0
Tax (expense) benefit	0	0	0
Other comprehensive income/(loss)	(27)	1	1
Net	$ (33)	$ (6)	$ (7)