Other Income and Other Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other income:
Interest income	$ 1,891	$ 477
Debt return on Four Corners SCR deferral (Note 4)	2,092	0
Miscellaneous	2	3
Total other income	3,985	480
Other expense:
Non-operating costs	(1,646)	(1,959)
Investment losses — net	(176)	(301)
Miscellaneous	(1,407)	(1,420)
Total other expense	(3,229)	(3,680)
Arizona Public Service Company
Other income:
Interest income	1,678	338
Debt return on Four Corners SCR deferral (Note 4)	2,092	0
Miscellaneous	2	4
Total other income	3,772	342
Other expense:
Non-operating costs	(1,539)	(1,752)
Miscellaneous	(1,406)	(1,376)
Total other expense	$ (2,945)	$ (3,128)