Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Selected Quarterly Financial Information [Line Items]
OPERATING REVENUES	$ 759,659	$ 1,183,322	$ 944,587	$ 677,728	$ 739,199	$ 1,166,922	$ 915,394	$ 677,167	$ 3,565,296	$ 3,498,682	$ 3,495,443
Operations and maintenance	266,149	224,305	214,013	219,976	208,277	217,568	242,279	243,195	924,443	911,319	868,377
Operating income	90,610	466,082	304,229	73,506	122,816	451,258	231,748	50,162	934,427	855,984	854,602
Income taxes	20,775	144,319	88,967	4,211	27,309	141,446	65,742	1,914	258,272	236,411	237,720
Net income	26,502	280,945	172,317	28,185	58,119	267,900	126,182	9,326	507,949	461,527	456,190
Net income attributable to common shareholders	$ 21,629	$ 276,072	$ 167,443	$ 23,312	$ 53,246	$ 263,027	$ 121,308	$ 4,453	$ 488,456	$ 442,034	$ 437,257
EARNINGS PER WEIGHTED-AVERAGE COMMON SHARE OUTSTANDING
Net income attributable to common shareholders - basic (in dollars per share)	$ 0.19	$ 2.47	$ 1.50	$ 0.21	$ 0.48	$ 2.36	$ 1.09	$ 0.04	$ 4.37	$ 3.97	$ 3.94
Net income attributable to common shareholders — diluted (in dollars per share)	$ 0.19	$ 2.46	$ 1.49	$ 0.21	$ 0.47	$ 2.35	$ 1.08	$ 0.04	$ 4.35	$ 3.95	$ 3.92
ARIZONA PUBLIC SERVICE COMPANY
Selected Quarterly Financial Information [Line Items]
Operating revenues	$ 756,549	$ 1,178,106	$ 942,615	$ 676,869	$ 737,006	$ 1,166,359	$ 909,757	$ 676,632	$ 3,554,139	$ 3,489,754	$ 3,492,357
Operations and maintenance	255,361	215,264	208,286	212,218	197,319	209,366	233,712	238,711	891,129	879,108	853,135
Operating income	79,258	322,053	212,790	65,468	95,765	307,601	165,684	48,930	679,569	617,980	611,984
Income taxes									269,168	245,842	245,841
Net income									523,802	481,634	469,207
Net income attributable to common shareholders	$ 27,783	$ 284,256	$ 169,108	$ 23,162	$ 58,480	$ 269,220	$ 127,188	$ 7,253	$ 504,309	$ 462,141	$ 450,274