Other Income and Other Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Nov. 06, 2020
Other income:
Interest income	$ 12,210,000	$ 10,377,000	$ 8,647,000
Investment gains (losses) — net	2,358,000	0	0
Miscellaneous	149,000	63,000	96,000
Total other income	56,703,000	50,263,000	24,896,000
Other expense:
Non-operating costs	(12,400,000)	(10,663,000)	(10,076,000)
Investment gains (losses) — net	0	(1,835,000)	(417,000)
Miscellaneous	(45,376,000)	(5,382,000)	(7,473,000)
Total other expense	(57,776,000)	(17,880,000)	(17,966,000)
ARIZONA PUBLIC SERVICE COMPANY
Other income:
Interest income	9,621,000	6,998,000	6,496,000
Miscellaneous	148,000	63,000	97,000
Total other income	51,755,000	46,884,000	22,746,000
Other expense:
Non-operating costs	(10,659,000)	(9,612,000)	(9,462,000)
Miscellaneous	(43,035,000)	(3,378,000)	(5,830,000)
Total other expense	(53,694,000)	(12,990,000)	(15,292,000)
ACC | Coal Community Transition Plan
Other expense:
Amount funded by shareholders	25,200,000			$ 25,000,000
ACC | Navajo Nation, Electrification Projects | Coal Community Transition Plan
Other expense:
Amount funded by shareholders	10,000,000			$ 10,000,000
SCR deferral
Other income:
Debt return on Four Corners SCR	26,121,000	19,541,000	16,153,000
SCR deferral | ARIZONA PUBLIC SERVICE COMPANY
Other income:
Debt return on Four Corners SCR	26,121,000	19,541,000	16,153,000
Octotillo deferral
Other income:
Debt return on Four Corners SCR	15,865,000	20,282,000	0
Octotillo deferral | ARIZONA PUBLIC SERVICE COMPANY
Other income:
Debt return on Four Corners SCR	$ 15,865,000	$ 20,282,000	$ 0