Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	$ 5,135,730	$ 4,935,912
OCI (loss) before reclassifications	24	(6,473)
Amounts reclassified from accumulated other comprehensive loss	5,822	5,293
Reclassification of income tax effect related to tax reform	(8,552)
Ending balance	5,348,705	5,135,730
Pension and Other Postretirement Benefits
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(42,440)	(39,070)
OCI (loss) before reclassifications	102	(6,438)
Amounts reclassified from accumulated other comprehensive loss	4,295	3,068
Reclassification of income tax effect related to tax reform	(7,954)
Ending balance	(45,997)	(42,440)
Derivative Instruments
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(2,562)	(4,752)
OCI (loss) before reclassifications	(78)	(35)
Amounts reclassified from accumulated other comprehensive loss	1,527	2,225
Reclassification of income tax effect related to tax reform	(598)
Ending balance	(1,711)	(2,562)
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(45,002)	(43,822)
Reclassification of income tax effect related to tax reform	(8,552)
Ending balance	(47,708)	(45,002)
ARIZONA PUBLIC SERVICE COMPANY
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	5,385,869	5,037,970
OCI (loss) before reclassifications	(404)	(6,919)
Amounts reclassified from accumulated other comprehensive loss	5,318	5,359
Reclassification of income tax effect related to tax reform	(5,038)
Ending balance	5,786,797	5,385,869
ARIZONA PUBLIC SERVICE COMPANY \| Pension and Other Postretirement Benefits
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(24,421)	(20,671)
OCI (loss) before reclassifications	(326)	(6,884)
Amounts reclassified from accumulated other comprehensive loss	3,791	3,134
Reclassification of income tax effect related to tax reform	(4,440)
Ending balance	(25,396)	(24,421)
ARIZONA PUBLIC SERVICE COMPANY \| Derivative Instruments
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(2,562)	(4,752)
OCI (loss) before reclassifications	(78)	(35)
Amounts reclassified from accumulated other comprehensive loss	1,527	2,225
Reclassification of income tax effect related to tax reform	(598)
Ending balance	(1,711)	(2,562)
ARIZONA PUBLIC SERVICE COMPANY \| Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(26,983)	(25,423)
Reclassification of income tax effect related to tax reform	(5,038)
Ending balance	$ (27,107)	$ (26,983)

Tax Cuts And Jobs Act Of 2017, Reclassification From AOCI To Retained Earnings,Tax Effect

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Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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