Amounts in Accumulated Other Comprehensive Income, Exclusive of Tax Impacts, that have not yet been Recognized as Components of Net Periodic Benefit Costs (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013
Pension Benefits
Accumulated other comprehensive loss (income)
Net transition obligation	$ 1
Net prior service credit	(10)
Total	(9)
Postretirement Benefits
Accumulated other comprehensive loss (income)
Net transition obligation	0
Net prior service credit	(9)
Total	$ (9)