Fair Value Measurements (Schedule Of Fair Value Of Derivatives, Net Of Legal Right To Offset Derivative Settlements) (Details) (Significant Other Observable Inputs (Level 2) [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2012		Sep. 30, 2011
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Guaranteed investment contract	$ 14	[1]	$ 14	[1]
Derivatives relating to interest rates	2	[2]	3	[2]
Derivatives relating to foreign currency	2	[2]
Total assets at fair value	18		17
Derivatives relating to foreign currency	36	[2]	41	[2]
Hedged long-term debt	60	[3]	61	[3]
Total liabilities at fair value	$ 96		$ 102

[1] Included in "Other assets" in the Consolidated Balance Sheets.

[2] Included in "Prepaid expenses and other current assets", "Other assets", "Accounts payable and accrued liabilities" or "Other liabilities" in the Consolidated Balance Sheets.

[3] Included in "Current portion of long-term debt" and "Long-term debt" in the Consolidated Balance Sheets.