Interest Expense (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Debt Instrument [Line Items]
Interest expense	$ 304	[1]	$ 373	[1]	$ 371	[1]
Amortization of debt premiums/discounts, net	(15)	[1],[2]	(18)	[1],[2]	(32)	[1],[2]
Amortization of deferred financing costs	(10)	[1]	(12)	[1]	(11)	[1]
Non-cash losses on debt extinguishments	(13)	[1]	(9)	[1]	(4)	[1]
Change in accrued interest	16	[1]	4	[1]	(4)	[1]
Interest paid	$ 282	[1],[3]	$ 338	[1],[3]	$ 320	[1],[3]

[1] Interest expense and interest paid for 2013, 2012 and 2011 includes cash prepayment premiums of approximately $23 million, $21 million and $5 million, respectively.

[2] Primarily represents the amortization of the debt discount on our Debentures, which is non-cash interest expense.

[3] Does not include capitalized interest of $6 million, $6 million and $4 million during 2013, 2012 and 2011, respectively.