CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
NET INCOME	$ 219,436	$ 198,459	$ 259,950	$ 233,325
Derivative instruments:
Net unrealized gain, net of tax benefit (expense)	870	(1,549)	1,132	(1,257)
Reclassification of net realized gain, net of tax benefit (expense)	0	262	0	282
Pension and other postretirement benefit activity, net of tax expense (benefit)	64	(1,009)	1,086	196
Total other comprehensive income	934	(2,296)	2,218	(779)
COMPREHENSIVE INCOME	220,370	196,163	262,168	232,546
Less: Comprehensive income attributable to noncontrolling interests	3,739	4,874	8,612	9,747
COMPREHENSIVE INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	216,631	191,289	253,556	222,799
APS
NET INCOME	223,487	201,992	263,647	242,210
Derivative instruments:
Net unrealized gain, net of tax benefit (expense)	0	0	0	292
Reclassification of net realized gain, net of tax benefit (expense)	0	262	0	282
Pension and other postretirement benefit activity, net of tax expense (benefit)	159	(1,090)	1,086	(77)
Total other comprehensive income	159	(828)	1,086	497
COMPREHENSIVE INCOME	223,646	201,164	264,733	242,707
Less: Comprehensive income attributable to noncontrolling interests	3,739	4,874	8,612	9,747
COMPREHENSIVE INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS	$ 219,907	$ 196,290	$ 256,121	$ 232,960