CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands		Total	Common Stock	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	APS	APS Common Stock	APS Additional Paid-In Capital	APS Retained Earnings	APS Accumulated Other Comprehensive Income (Loss)	APS Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2019			112,540,126	103,546					71,264,947
Balance at beginning of period at Dec. 31, 2019		$ 5,553,188	$ 2,659,561	$ (9,427)	$ 2,837,610	$ (57,096)	$ 122,540	$ 5,998,803	$ 178,162	$ 2,721,696	$ 3,011,927	$ (35,522)	$ 122,540
Increase (Decrease) in Shareholders' Equity
Net Income		233,325			223,578		9,747	242,210			232,463		9,747
Other comprehensive income (loss)		(779)				(779)		497				497
Dividends on common stock		(176,079)			(176,079)			(176,000)			(176,000)
Issuance of common stock (in shares)			50,998
Issuance of common stock		5,957	$ 5,957
Purchase of treasury stock (in shares)	[1]			(33,070)
Purchase of treasury stock	[1]	(3,010)		$ (3,010)
Reissuance of treasury stock for stock-based compensation and other (in shares)				100,633
Reissuance of treasury stock for stock-based compensation and other		9,247		$ 9,247
Other								(1)			(1)
Capital activities by noncontrolling interests		(11,372)					(11,372)	(11,372)					(11,372)
Ending balance (in shares) at Jun. 30, 2020			112,591,124	35,983					71,264,947
Balance at end of period at Jun. 30, 2020		5,610,477	$ 2,665,518	$ (3,190)	2,885,109	(57,875)	120,915	6,054,137	$ 178,162	2,721,696	3,068,389	(35,025)	120,915
Beginning balance (in shares) at Mar. 31, 2020			112,563,610	72,302					71,264,947
Balance at beginning of period at Mar. 31, 2020		5,596,832	$ 2,664,387	$ (7,000)	2,867,610	(55,579)	127,414	6,040,344	$ 178,162	2,721,696	3,047,269	(34,197)	127,414
Increase (Decrease) in Shareholders' Equity
Net Income		198,459			193,585		4,874	201,992			197,118		4,874
Other comprehensive income (loss)		(2,296)				(2,296)		(828)				(828)
Dividends on common stock		(176,086)			(176,086)			(176,000)			(176,000)
Issuance of common stock (in shares)			27,514
Issuance of common stock		1,131	$ 1,131
Purchase of treasury stock (in shares)	[2]			(12,346)
Purchase of treasury stock	[2]	(924)		$ (924)
Reissuance of treasury stock for stock-based compensation and other (in shares)				48,665
Reissuance of treasury stock for stock-based compensation and other		4,734		$ 4,734
Other		(1)					(1)	1			2		(1)
Capital activities by noncontrolling interests		(11,372)					(11,372)	(11,372)					(11,372)
Ending balance (in shares) at Jun. 30, 2020			112,591,124	35,983					71,264,947
Balance at end of period at Jun. 30, 2020		$ 5,610,477	$ 2,665,518	$ (3,190)	2,885,109	(57,875)	120,915	6,054,137	$ 178,162	2,721,696	3,068,389	(35,025)	120,915
Beginning balance (in shares) at Dec. 31, 2020		112,760,051	112,760,051	72,006					71,264,947
Balance at beginning of period at Dec. 31, 2020		$ 5,752,793	$ 2,677,482	$ (6,289)	3,025,106	(62,796)	119,290	6,345,185	$ 178,162	2,871,696	3,216,955	(40,918)	119,290
Increase (Decrease) in Shareholders' Equity
Net Income		259,950			251,338		8,612	263,647			255,035		8,612
Other comprehensive income (loss)		2,218				2,218		1,086				1,086
Dividends on common stock		(187,176)			(187,176)			(187,000)			(187,000)
Issuance of common stock (in shares)			59,652
Issuance of common stock		14,533	$ 14,533
Purchase of treasury stock (in shares)	[1]			(17,437)
Purchase of treasury stock	[1]	(1,333)		$ (1,333)
Reissuance of treasury stock for stock-based compensation and other (in shares)				53,290
Reissuance of treasury stock for stock-based compensation and other		4,543		$ 4,543
Other		(1)			(2)		1	0			(1)		1
Capital activities by noncontrolling interests		$ (10,628)					(10,628)	(10,628)					(10,628)
Ending balance (in shares) at Jun. 30, 2021		112,819,703	112,819,703	36,153					71,264,947
Balance at end of period at Jun. 30, 2021		$ 5,834,899	$ 2,692,015	$ (3,079)	3,089,266	(60,578)	117,275	6,412,290	$ 178,162	2,871,696	3,284,989	(39,832)	117,275
Beginning balance (in shares) at Mar. 31, 2021			112,791,565	44,338					71,264,947
Balance at beginning of period at Mar. 31, 2021		5,806,680	$ 2,687,052	$ (3,776)	3,060,752	(61,512)	124,164	6,386,275	$ 178,162	2,871,696	3,252,244	(39,991)	124,164
Increase (Decrease) in Shareholders' Equity
Net Income		219,436			215,697		3,739	223,487			219,748		3,739
Other comprehensive income (loss)		934				934		159				159
Dividends on common stock		(187,181)			(187,181)			(187,000)			(187,000)
Issuance of common stock (in shares)			28,138
Issuance of common stock		4,963	$ 4,963
Reissuance of treasury stock for stock-based compensation and other (in shares)				8,185
Reissuance of treasury stock for stock-based compensation and other		697		$ 697
Other		(2)			(2)			(3)			(3)
Capital activities by noncontrolling interests		$ (10,628)					(10,628)	(10,628)					(10,628)
Ending balance (in shares) at Jun. 30, 2021		112,819,703	112,819,703	36,153					71,264,947
Balance at end of period at Jun. 30, 2021		$ 5,834,899	$ 2,692,015	$ (3,079)	$ 3,089,266	$ (60,578)	$ 117,275	$ 6,412,290	$ 178,162	$ 2,871,696	$ 3,284,989	$ (39,832)	$ 117,275

[1] Primarily represents shares of common stock withheld from certain stock awards for tax purposes.

[2] Primarily represents shares of common stock withheld from certain stock awards for tax purposes.