Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	$ 4,935,912	$ 4,719,457
Ending balance	5,135,730	4,935,912
Pension and Other Postretirement Benefits
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(39,070)	(37,593)
OCI (loss) before reclassifications	(6,438)	(4,509)
Amounts reclassified from accumulated other comprehensive loss	3,068	3,032
Ending balance	(42,440)	(39,070)
Derivative Instruments
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(4,752)	(7,155)
OCI (loss) before reclassifications	(35)	(538)
Amounts reclassified from accumulated other comprehensive loss	2,225	2,941
Ending balance	(2,562)	(4,752)
Total
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(43,822)	(44,748)
OCI (loss) before reclassifications	(6,473)	(5,047)
Amounts reclassified from accumulated other comprehensive loss	5,293	5,973
Ending balance	(45,002)	(43,822)
ARIZONA PUBLIC SERVICE COMPANY
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	5,037,970	4,814,794
Ending balance	5,385,869	5,037,970
ARIZONA PUBLIC SERVICE COMPANY \| Pension and Other Postretirement Benefits
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(20,671)	(19,942)
OCI (loss) before reclassifications	(6,884)	(3,821)
Amounts reclassified from accumulated other comprehensive loss	3,134	3,092
Ending balance	(24,421)	(20,671)
ARIZONA PUBLIC SERVICE COMPANY \| Derivative Instruments
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(4,752)	(7,155)
OCI (loss) before reclassifications	(35)	(538)
Amounts reclassified from accumulated other comprehensive loss	2,225	2,941
Ending balance	(2,562)	(4,752)
ARIZONA PUBLIC SERVICE COMPANY \| Total
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(25,423)	(27,097)
OCI (loss) before reclassifications	(6,919)	(4,359)
Amounts reclassified from accumulated other comprehensive loss	5,359	6,033
Ending balance	$ (26,983)	$ (25,423)

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 55
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=84158357&loc=d3e1436-108581

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 55
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=84158357&loc=d3e1436-108581

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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No definition available.

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 55
-Paragraph 4I
-URI http://asc.fasb.org/extlink&oid=84234705&loc=SL4590271-111686

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 16
-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4568740-111683

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-Publisher FASB
-Name Accounting Standards Codification
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-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=96868048&loc=SL4568447-111683

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