Concentrations - Revenue by Geographic Region (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues	$ 111	$ 101	$ 99	$ 125	$ 104	$ 126	$ 147	$ 143	$ 436	$ 520	$ 639
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									291	322	409
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									74	123	128
Asia/Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									36	45	45
Latin America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									19	20	41
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Total revenues									$ 16	$ 10	$ 16