Property and Equipment, Net - Summary of Property and Equipment (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Cost	$ 1,052	$ 1,024
Accumulated depreciation	(630)	(596)
Net	422	428
Capitalized Software [Member]
Property, Plant and Equipment [Line Items]
Cost	686	650
Accumulated depreciation	(473)	(449)
Net	213	201
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Cost	282	281
Accumulated depreciation	(149)	(139)
Net	133	142
Building and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Cost	18	17
Accumulated depreciation	(8)	(8)
Net	10	9
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Cost	66	76
Accumulated depreciation
Net	$ 66	$ 76