Debt and Other Obligations - Schedule of Future Years Payment (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013
Future Years Payment [Line Items]
2014	$ 17
2015	34
2016	14
2017	303
2018	265
Thereafter	427
Less: executory costs and interest	(24)
Total	1,036
Principal Payments on Long Term Debt [Member]
Future Years Payment [Line Items]
2014	12
2015	30
2016	11
2017	300
2018	262
Thereafter	403
Total	1,018
Capital Lease Obligations, Due Through 2031 [Member]
Future Years Payment [Line Items]
2014	5
2015	4
2016	3
2017	3
2018	3
Thereafter	24
Less: executory costs and interest	(24)
Total	$ 18