Income Taxes - Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Beginning and Ending Amounts of Unrecognized Tax Benefits
Unrecognized tax benefit - opening balance	$ 23	$ 25	$ 57
Gross increases - tax positions in prior periods	8	6
Gross decreases - tax positions in prior periods	(5)	(6)	(3)
Gross increases - tax positions in current period	1		6
Decrease related to lapsing of statute of limitations	(2)	(2)
Decrease due to disposals			(32)
Settlements	(1)		(3)
Unrecognized tax benefit - ending balance	$ 24	$ 23	$ 25