Long-Term Debt - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		6 Months Ended	9 Months Ended				1 Months Ended					1 Months Ended		6 Months Ended
	Aug. 31, 2011	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Apr. 30, 2012 Term Loan A One Facilities With Final Maturity Of November Two Thousand Twelve [Member]	Apr. 30, 2012 Term Loan B One Facilities With Final Maturity Of November Two Thousand Thirteen [Member]	Apr. 30, 2012 Term Loan A Three Facilities With Final Maturity Of February Two Thousand Sixteen [Member]	Feb. 29, 2012 Senior Secured First Lien Notes Due 2022 [Member]	Aug. 31, 2011 Aggregate Principal Amount Of Notes [Member]	Aug. 31, 2011 Senior Secured First Lien Notes Due 2020 [Member]	Aug. 31, 2011 Senior Unsecured Notes Due 2022 [Member]	Aug. 31, 2011 Senior Secured Second Lien Toggle Notes Due 2016 [Member]	Aug. 31, 2011 Senior Secured Second Lien Notes Due 2016 [Member]	Jun. 30, 2011 Senior Secured Second Lien Notes Due 2014 [Member]	Jun. 30, 2011 Senior Secured Second Lien Notes Due 2017 [Member]
Line of Credit Facility [Line Items]
Term loans							$ 75	$ 651
Debt instrument, maturities range, end									Feb. 01, 2016
Debt instrument, principal amount										1,350	5,000	3,000	2,000
Debt instrument, stated interest										5.875%		6.50%	7.50%		9.25%	9.125%	9.875%
Net proceeds from debt issuances to redeem all of outstanding														1,578
Debt Instrument Stated Interest In Cash, Percentage														9.625%
Debt Instrument Stated Interest In Kind, Percentage	10.375%
Percentage of redemption price of principal amount	106.513%														106.783%	104.563%	109.875%
Senior notes															3,200
Pretax loss on retirement of debt	406
Redemption of aggregate principal amount																1,000	108
Pretax loss on retirement of debt			$ (406)	$ 75		$ (481)