Debt - Long-Term Debt (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Total debt	$ 2,413	$ 1,615
Less: Long-term debt due in one year	(18)	(10)
Long-term debt	2,395	1,605
Term Loan [Member]
Debt Instrument [Line Items]
Initial Principal Amount	1,500
Maturity Date	Mar. 19, 2020
Total debt	1,482
Notes [Member]
Debt Instrument [Line Items]
Initial Principal Amount	900
Maturity Date	Aug. 15, 2020
Total debt	900	900
Term Facility [Member]
Debt Instrument [Line Items]
Initial Principal Amount	700
Maturity Date	Feb. 08, 2018
Total debt		691
Co-generation Unit Financing Arrangement [Member]
Debt Instrument [Line Items]
Initial Principal Amount	16
Maturity Date	Feb. 01, 2016
Total debt	6	10
Lease Financing [Member]
Debt Instrument [Line Items]
Total debt	$ 25	$ 14