Retirement Benefit Liabilities (Tables)

6 Months Ended

Mar. 31, 2017

Compensation and Retirement Disclosure [Abstract]

Summary of retirement benefit liabilities

Retirement benefit liabilities consisted of the following (in millions):

	March 31, 2017			September 30, 2016
Retiree medical liability	$	438		$	447
Pension liability	267			283
Other	14			13
Subtotal	719			743
Less: current portion (included in compensation and benefits, Note 16)	(39		)	(40		)
Retirement benefits	$	680		$	703

Components of net periodic pension and retiree medical expense

The components of net periodic pension and retiree medical expense included in continuing operations for the three months ended March 31 are as follows (in millions):

	2017					2016
	Pension			Retiree Medical		Pension			Retiree Medical
Interest cost	$	13		$	3	$	27		$	5
Assumed return on plan assets	(24		)	—		(25		)	—
Amortization of prior service costs	—			—		—			—
Recognized actuarial loss	8			3		6			3
Total expense (income)	$	(3	)	$	6	$	8		$	8

The components of net periodic pension and retiree medical expense included in continuing operations for the six months ended March 31 are as follows (in millions):

	2017						2016
	Pension			Retiree Medical			Pension			Retiree Medical
Interest cost	$	26		$	7		$	33		$	9
Assumed return on plan assets	(47		)	—			(50		)	—
Amortization of prior service costs	—			(1		)	—			—
Recognized actuarial loss	15			7			12			6
Total expense (income)	$	(6	)	$	13		$	(5	)	$	15