SCHEDULE II - RESERVE FOR UNCOLLECTIBLES (Details) - Reserve for uncollectibles. - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Pinnacle West
Changes in reserve for uncollectibles
Balance at beginning of period	$ 2,513	$ 3,037	$ 3,125
Additions, Charged to cost and expenses	10,870	6,836	4,025
Additions, Charged to other accounts	0	0	0
Deductions	9,314	7,360	4,113
Balance at end of period	4,069	2,513	3,037
ARIZONA PUBLIC SERVICE COMPANY
Changes in reserve for uncollectibles
Balance at beginning of period	2,513	3,037	3,125
Additions, Charged to cost and expenses	10,870	6,836	4,025
Additions, Charged to other accounts	0	0	0
Deductions	9,314	7,360	4,113
Balance at end of period	$ 4,069	$ 2,513	$ 3,037

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Amount of valuation and qualifying accounts and reserves.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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Amount of increase in valuation and qualifying accounts and reserves from charge to accounts other than cost and expense.

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