New Accounting Standards - Narrative (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
Mar. 31, 2015	Sep. 30, 2014
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Debt issuance cost	$ 27us-gaap_DebtIssuanceCosts	$ 30us-gaap_DebtIssuanceCosts

Amount of debt issuance costs (for example, but not limited to, legal, accounting, broker, and regulatory fees).

No definition available.