CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
OPERATING REVENUES	$ 1,190,787	$ 1,268,034	$ 2,800,818	$ 2,934,871
OPERATING EXPENSES
Fuel and purchased power	344,862	389,936	817,672	844,133
Operations and maintenance	238,582	246,545	711,759	780,624
Depreciation and amortization	149,450	145,971	445,531	436,232
Taxes other than income taxes	53,809	51,375	163,989	158,582
Other expenses	794	900	1,904	8,497
Total	787,497	834,727	2,140,855	2,228,068
OPERATING INCOME	403,290	433,307	659,963	706,803
OTHER INCOME (DEDUCTIONS)
Allowance for equity funds used during construction	5,917	12,259	24,677	39,411
Pension and other postretirement non-service credits - net	5,752	12,449	17,240	37,314
Other income (Note 9)	15,191	6,958	35,245	17,541
Other expense (Note 9)	(5,740)	(5,063)	(14,448)	(12,063)
Total	21,120	26,603	62,714	82,203
INTEREST EXPENSE
Interest charges	57,481	61,605	175,599	181,267
Allowance for borrowed funds used during construction	(3,486)	(5,913)	(14,645)	(18,959)
Total	53,995	55,692	160,954	162,308
INCOME BEFORE INCOME TAXES	370,415	404,218	561,723	626,698
INCOME TAXES	53,266	84,333	72,764	127,107
NET INCOME	317,149	319,885	488,959	499,591
Less: Net income attributable to noncontrolling interests (Note 6)	4,873	4,873	14,620	14,620
NET INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	$ 312,276	$ 315,012	$ 474,339	$ 484,971
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - BASIC (in shares)	112,463	112,148	112,408	112,094
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - DILUTED (in shares)	112,746	112,533	112,739	112,499
EARNINGS PER WEIGHTED-AVERAGE COMMON SHARE OUTSTANDING
Net income attributable to common shareholders - basic (in dollars per share)	$ 2.78	$ 2.81	$ 4.22	$ 4.33
Net income attributable to common shareholders - diluted (in dollars per share)	$ 2.77	$ 2.80	$ 4.21	$ 4.31
APS
OPERATING REVENUES	$ 1,190,787	$ 1,267,997	$ 2,800,818	$ 2,931,966
OPERATING EXPENSES
Fuel and purchased power	344,862	389,889	817,672	862,037
Operations and maintenance	235,440	226,346	699,958	732,946
Depreciation and amortization	149,428	145,949	445,467	434,594
Taxes other than income taxes	53,798	51,366	163,957	157,877
Other expenses	794	900	1,904	1,497
Total	784,322	814,450	2,128,958	2,188,951
OPERATING INCOME	406,465	453,547	671,860	743,015
OTHER INCOME (DEDUCTIONS)
Allowance for equity funds used during construction	5,917	12,259	24,677	39,411
Pension and other postretirement non-service credits - net	6,133	12,812	18,389	38,398
Other income (Note 9)	14,534	6,153	32,641	16,160
Other expense (Note 9)	(2,826)	(3,361)	(10,132)	(9,679)
Total	23,758	27,863	65,575	84,290
INTEREST EXPENSE
Interest charges	53,812	58,551	164,068	172,440
Allowance for borrowed funds used during construction	(3,486)	(5,913)	(14,645)	(18,959)
Total	50,326	52,638	149,423	153,481
INCOME BEFORE INCOME TAXES	379,897	428,772	588,012	673,824
INCOME TAXES	56,154	85,533	76,070	133,415
NET INCOME	323,743	343,239	511,942	540,409
Less: Net income attributable to noncontrolling interests (Note 6)	4,873	4,873	14,620	14,620
NET INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	$ 318,870	$ 338,366	$ 497,322	$ 525,789