Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Unrecognized Tax Benefits [Line Items]
Balance at January 1,	$ 41	$ 42	$ 33
Additions for tax positions of prior years	4	4	6
Reductions for tax positions of prior years	(2)	(6)	(2)
Additions based on tax positions related to the current year	10	9	9
Settlements		(4)	(1)
Lapse of statute of limitations	(1)	(4)	(3)
Balance at December 31,	$ 52	$ 41	$ 42