Accumulated Other Comprehensive Income (Loss)

12 Months Ended

Sep. 30, 2021

Stockholders Equity Note [Abstract]

Accumulated Other Comprehensive Income (Loss)

Note P. Accumulated Other Comprehensive Income (Loss)

Changes in each component of AOCI, net of tax, are as follows for fiscal 2020 and 2021:

	Currency Translation Adjustment			Unrealized Gains on Investment			Pension and Other Postretirement Benefit Liability Adjustment			Total
	(In millions)
Balance at September 30, 2019 attributable to    Cabot Corporation	$	(338	)	$	1		$	(54	)	$	(391	)
Other comprehensive income (loss) before reclassifications		42			—			3			45
Amounts reclassified from AOCI		(3	)		—			6			3
Adoption of accounting standards		(3	)		(1	)		1			(3	)
Less: Other comprehensive income (loss) attributable to    noncontrolling interests		5			—			—			5
Balance at September 30, 2020 attributable to    Cabot Corporation		(307	)		—			(44	)		(351	)
Other comprehensive income (loss) before reclassifications		52			—			20			72
Amounts reclassified from AOCI		(3	)		—			—			(3	)
Less: Other comprehensive income (loss) attributable to    noncontrolling interests		7			—			—			7
Balance at September 30, 2021 attributable to    Cabot Corporation	$	(265	)	$	—		$	(24	)	$	(289	)

The amounts reclassified out of AOCI and into the Consolidated Statements of Operations for fiscal 2021, 2020 and 2019 are as follows:

	Affected Line Item in the Consolidated	Years Ended September 30
	Statements of Operations	2021			2020			2019
		(In Millions)
Derivatives: net investment hedges
(Gains) losses reclassified to interest    expense	Interest expense	$	(5	)	$	(5	)	$	(5	)
(Gains) losses excluded from effectiveness    testing and amortized to interest expense	Interest expense		2			2			1
Pension and other postretirement benefit    liability adjustment
Amortization of actuarial losses and prior service cost (credit)	Net Periodic Benefit Cost - see Note M for details		3			3			1
Settlement and curtailment loss (gain)	Net Periodic Benefit Cost - see Note M for details		5			4			(7	)
Specialty Fluids divestiture	Specialty Fluids loss on sale and asset impairment - see Note D for details		—			—			(3	)
Total before tax		$	5		$	4		$	(13	)