The tables below present changes in AOCI, net of tax, during the three and six months ended March 31, 2019 and 2018:



Three Months Ended March 31, 2019	Postretirement Benefit Plans			Derivative Instruments			Total
AOCI — December 31, 2018	$	(6,500	)	$	(19,726	)	$	(26,226	)
Net losses on interest rate contract	—			(621		)	(621		)
Reclassifications of benefit plan actuarial losses and net prior service benefits	133			—			133
Reclassifications of net losses on IRPAs	—			619			619
AOCI — March 31, 2019	$	(6,367	)	$	(19,728	)	$	(26,095	)

Three Months Ended March 31, 2018	Postretirement Benefit Plans			Derivative Instruments			Total
AOCI — December 31, 2017	$	(8,775	)	$	(17,204	)	$	(25,979	)
Reclassifications of benefit plan actuarial losses and net prior service benefits	220			—			220
Reclassifications of net losses on IRPAs	—			592			592
AOCI — March 31, 2018	$	(8,555	)	$	(16,612	)	$	(25,167	)



Six Months Ended March 31, 2019	Postretirement Benefit Plans			Derivative Instruments			Total
AOCI — September 30, 2018	$	(4,920	)	$	(15,409	)	$	(20,329	)
Net losses on interest rate contract	—			(1,819		)	(1,819		)
Reclassifications of benefit plan actuarial losses and net prior service benefits	265			—			265
Reclassifications of net losses on IRPAs	—			1,239			1,239
Reclassification of stranded income tax effects related to TCJA	(1,712		)	(3,739		)	(5,451		)
AOCI — March 31, 2019	$	(6,367	)	$	(19,728	)	$	(26,095	)

Six Months Ended March 31, 2018	Postretirement Benefit Plans			Derivative Instruments			Total
AOCI — September 30, 2017	$	(8,995	)	$	(17,796	)	$	(26,791	)
Reclassifications of benefit plan actuarial losses and net prior service benefits	440			—			440
Reclassifications of net losses on IRPAs	—			1,184			1,184
AOCI — March 31, 2018	$	(8,555	)	$	(16,612	)	$	(25,167	)