CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
NET INCOME	$ 351,245	$ 317,149	$ 584,570	$ 488,959
Derivative instruments:
Net unrealized gain, net of tax expense	(659)	0	(1,916)	0
Reclassification of net realized loss, net of tax benefit	0	218	282	950
Pension and other postretirement benefits activity, net of tax expense	1,043	880	1,239	220
Total other comprehensive income (loss)	384	1,098	(395)	1,170
COMPREHENSIVE INCOME	351,629	318,247	584,175	490,129
Less: Comprehensive income attributable to noncontrolling interests	4,873	4,873	14,620	14,620
COMPREHENSIVE INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	346,756	313,374	569,555	475,509
APS
NET INCOME	355,236	323,743	597,446	511,942
Derivative instruments:
Net unrealized gain, net of tax expense	0	0	292	0
Reclassification of net realized loss, net of tax benefit	0	218	282	950
Pension and other postretirement benefits activity, net of tax expense	900	755	823	(146)
Total other comprehensive income (loss)	900	973	1,397	804
COMPREHENSIVE INCOME	356,136	324,716	598,843	512,746
Less: Comprehensive income attributable to noncontrolling interests	4,873	4,873	14,620	14,620
COMPREHENSIVE INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	$ 351,263	$ 319,843	$ 584,223	$ 498,126