Other Income and Other Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other income:
Interest income	$ 917	$ 65	$ 1,782	$ 370
Investment gains — net	119	0	119	13
Miscellaneous	55	6	154	2
Total other income	1,091	71	2,055	385
Other expense:
Non-operating costs	(1,978)	(2,502)	(7,338)	(6,636)
Investment losses — net	(231)	(450)	(759)	(1,508)
Miscellaneous	(2,784)	(2,253)	(4,398)	(3,941)
Total other expense	(4,993)	(5,205)	(12,495)	(12,085)
Arizona Public Service Company
Other income:
Interest income	683	0	1,278	181
Gain on disposition of property	441	183	1,009	5,504
Miscellaneous	354	384	1,395	1,239
Total other income	1,478	567	3,682	6,924
Other expense:
Non-operating costs	(1,970)	(2,714)	(7,889)	(7,398)
Loss on disposition of property	(3,214)	36	(4,471)	(1,048)
Miscellaneous	(1,078)	(1,098)	(3,930)	(4,510)
Total other expense	$ (6,262)	$ (3,776)	$ (16,290)	$ (12,956)