CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
OPERATING REVENUES	$ 1,268,034	$ 1,183,322	$ 2,934,871	$ 2,805,637
OPERATING EXPENSES
Fuel and purchased power	389,936	310,469	844,133	777,475
Operations and maintenance	246,545	230,839	780,624	677,895
Depreciation and amortization	145,971	133,912	436,232	387,278
Taxes other than income taxes	51,375	45,169	158,582	133,294
Other expenses	900	3,385	8,497	5,479
Total	834,727	723,774	2,228,068	1,981,421
OPERATING INCOME	433,307	459,548	706,803	824,216
OTHER INCOME (DEDUCTIONS)
Allowance for equity funds used during construction	12,259	12,728	39,411	32,666
Pension and other postretirement non-service credits - net	12,449	6,534	37,314	19,601
Other income (Note 9)	6,958	1,091	17,541	2,055
Other expense (Note 9)	(5,063)	(4,993)	(12,063)	(12,495)
Total	26,603	15,360	82,203	41,827
INTEREST EXPENSE
Interest charges	61,605	55,644	181,267	162,477
Allowance for borrowed funds used during construction	(5,913)	(6,000)	(18,959)	(15,378)
Total	55,692	49,644	162,308	147,099
INCOME BEFORE INCOME TAXES	404,218	425,264	626,698	718,944
INCOME TAXES	84,333	144,319	127,107	237,497
NET INCOME	319,885	280,945	499,591	481,447
Less: Net income attributable to noncontrolling interests (Note 6)	4,873	4,873	14,620	14,620
NET INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	$ 315,012	$ 276,072	$ 484,971	$ 466,827
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - BASIC (in shares)	112,148	111,835	112,094	111,787
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - DILUTED (in shares)	112,533	112,401	112,499	112,314
EARNINGS PER WEIGHTED-AVERAGE COMMON SHARE OUTSTANDING
Net income attributable to common shareholders - basic (in dollars per share)	$ 2.81	$ 2.47	$ 4.33	$ 4.18
Net income attributable to common shareholders - diluted (in dollars per share)	$ 2.80	$ 2.46	$ 4.31	$ 4.16
APS
OPERATING REVENUES	$ 1,267,997	$ 1,178,846	$ 2,931,966	$ 2,799,840
OPERATING EXPENSES
Fuel and purchased power	389,889	309,045	862,037	786,041
Operations and maintenance	226,346	222,374	732,946	657,157
Depreciation and amortization	145,949	133,486	434,594	386,010
Taxes other than income taxes	51,366	44,898	157,877	132,478
Other expenses	900	3,385	1,497	5,527
Total	814,450	713,188	2,188,951	1,967,213
OPERATING INCOME	453,547	465,658	743,015	832,627
OTHER INCOME (DEDUCTIONS)
Allowance for equity funds used during construction	12,259	12,728	39,411	32,666
Pension and other postretirement non-service credits - net	12,812	6,477	38,398	19,430
Other income (Note 9)	6,153	738	16,160	1,432
Other expense (Note 9)	(3,361)	(2,178)	(9,679)	(8,608)
Total	27,863	17,765	84,290	44,920
INTEREST EXPENSE
Interest charges	58,551	53,760	172,440	158,074
Allowance for borrowed funds used during construction	(5,913)	(6,000)	(18,959)	(15,378)
Total	52,638	47,760	153,481	142,696
INCOME BEFORE INCOME TAXES	428,772	435,663	673,824	734,851
INCOME TAXES	85,533	146,534	133,415	243,708
NET INCOME	343,239	289,129	540,409	491,143
Less: Net income attributable to noncontrolling interests (Note 6)	4,873	4,873	14,620	14,620
NET INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	$ 338,366	$ 284,256	$ 525,789	$ 476,523