Changes in Accumulated Other Comprehensive Loss (Tables)

9 Months Ended

Sep. 30, 2018

Accumulated Other Comprehensive Income (Loss) [Line Items]

Schedule of changes in accumulated other comprehensive loss including reclassification adjustments, net of tax, by component

The following table shows the changes in Pinnacle West's consolidated accumulated other comprehensive loss, including reclassification adjustments, net of tax, by component for the three and nine months ended September 30, 2018 and 2017 (dollars in thousands):

	Pension and Other Postretirement Benefits				Derivative Instruments				Total
Three Months Ended September 30
Balance June 30, 2018	$	(54,233	)		$	(2,391	)		$	(56,624	)
Amounts reclassified from accumulated other comprehensive loss	1,099			(a)	451			(b)	1,550
Balance September 30, 2018	$	(53,134	)		$	(1,940	)		$	(55,074	)
Balance June 30, 2017	$	(39,881	)		$	(3,745	)		$	(43,626	)
OCI (loss) before reclassifications	—				9				9
Amounts reclassified from accumulated other comprehensive loss	790			(a)	710			(b)	1,500
Balance September 30, 2017	$	(39,091	)		$	(3,026	)		$	(42,117	)

	Pension and Other Postretirement Benefits				Derivative Instruments				Total
Nine Months Ended September 30
Balance December 31, 2017	$	(42,440	)		$	(2,562	)		$	(45,002	)
OCI (loss) before reclassifications	(5,928		)		(96		)		(6,024		)
Amounts reclassified from accumulated other comprehensive loss	3,188			(a)	1,316			(b)	4,504
Reclassification of income tax effect related to tax reform	(7,954		)		(598		)		(8,552		)
Balance September 30, 2018	$	(53,134	)		$	(1,940	)		$	(55,074	)
Balance December 31, 2016	$	(39,070	)		$	(4,752	)		$	(43,822	)
OCI (loss) before reclassifications	(2,157		)		(754		)		(2,911		)
Amounts reclassified from accumulated other comprehensive loss	2,136			(a)	2,480			(b)	4,616
Balance September 30, 2017	$	(39,091	)		$	(3,026	)		$	(42,117	)

(a) These amounts primarily represent amortization of actuarial loss, and are included in the computation of net periodic pension cost.  See Note 5.

(b)

These amounts represent realized gains and losses and are included in the computation of fuel and purchased power costs and are subject to the PSA.  See Note 7.

APS

Accumulated Other Comprehensive Income (Loss) [Line Items]

Schedule of changes in accumulated other comprehensive loss including reclassification adjustments, net of tax, by component

The following table shows the changes in APS's consolidated accumulated other comprehensive loss, including reclassification adjustments, net of tax, by component for the three and nine months ended September 30, 2018 and 2017 (dollars in thousands): 

	Pension and Other Postretirement Benefits				Derivative Instruments				Total
Three Months Ended September 30
Balance June 30, 2018	$	(32,768	)		$	(2,391	)		$	(35,159	)
Amounts reclassified from accumulated other comprehensive loss	952			(a)	451			(b)	1,403
Balance September 30, 2018	$	(31,816	)		$	(1,940	)		$	(33,756	)
Balance June 30, 2017	$	(21,367	)		$	(3,745	)		$	(25,112	)
OCI (loss) before reclassifications	—				9				9
Amounts reclassified from accumulated other comprehensive loss	777			(a)	710			(b)	1,487
Balance September 30, 2017	$	(20,590	)		$	(3,026	)		$	(23,616	)

	Pension and Other Postretirement Benefits				Derivative Instruments				Total
Nine Months Ended September 30
Balance December 31, 2017	$	(24,421	)		$	(2,562	)		$	(26,983	)
OCI (loss) before reclassifications	(5,791		)		(96		)		(5,887		)
Amounts reclassified from accumulated other comprehensive loss	2,836			(a)	1,316			(b)	4,152
Reclassification of income tax effect related to tax reform	(4,440		)		(598		)		(5,038		)
Balance September 30, 2018	$	(31,816	)		$	(1,940	)		$	(33,756	)
Balance December 31, 2016	$	(20,671	)		$	(4,752	)		$	(25,423	)
OCI (loss) before reclassifications	(2,121		)		(754		)		(2,875		)
Amounts reclassified from accumulated other comprehensive loss	2,202			(a)	2,480			(b)	4,682
Balance September 30, 2017	$	(20,590	)		$	(3,026	)		$	(23,616	)

(a) These amounts primarily represent amortization of actuarial loss and are included in the computation of net periodic pension cost.  See Note 5.

(b)

These amounts represent realized gains and losses and are included in the computation of fuel and purchased power costs and are subject to the PSA.  See Note 7.