Pension and Other Postretirement Benefits (Tables)

6 Months Ended

Mar. 31, 2013

Compensation and Retirement Disclosure [Abstract]

Schedule of Defined Benefit Plans Disclosures

The components of net periodic benefit cost are as follows:

	Pension Benefits												Other Postretirement Benefits
	Three Months Ended March 31,						Six Months Ended March 31,						Three Months Ended March 31,					Six Months Ended March 31,
	2013			2012			2013			2012			2013		2012			2013			2012
	(in millions)
Service cost	$	12		$	9		$	22		$	19		$	—	$	—		$	—		$	—
Interest cost	9			10			18			20			—		1			—			1
Expected return on assets	(15		)	(13		)	(31		)	(27		)	—		—			—			—
Amortization of:
Prior service credit	(3		)	(3		)	(5		)	(5		)	—		(1		)	(1		)	(2		)
Actuarial loss	7			8			14			16			—		—			—			—
Total net periodic benefit cost	$	10		$	11		$	18		$	23		$	—	$	—		$	(1	)	$	(1	)