Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Preferred Stock	Preferred Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Common Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Capital in Excess of Par Value	Capital in Excess of Par Value Cumulative Effect, Period of Adoption, Adjusted Balance	Treasury Stock	Treasury Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Cumulative Net Income	Cumulative Net Income Cumulative Effect, Period of Adoption, Adjustment	Cumulative Net Income Cumulative Effect, Period of Adoption, Adjusted Balance	Cumulative Dividends	Cumulative Dividends Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive Income (loss)	Accumulated Other Comprehensive Income (loss) Cumulative Effect, Period of Adoption, Adjusted Balance	Noncontrolling Interests	Noncontrolling Interests Cumulative Effect, Period of Adoption, Adjusted Balance
Balances at beginning of period at Dec. 31, 2017	$ 14,925,452			$ 718,503		$ 372,449		$ 17,663,351		$ (64,559)		$ 5,316,580			$ (9,471,712)		$ (111,465)		$ 502,305
Comprehensive income:
Net income (loss)	830,019											804,954							25,065
Other comprehensive income (loss)	(41,288)																(18,304)		(22,984)
Total comprehensive income	788,731
Net change in noncontrolling interests	406,778							(43,101)											449,879
Amounts related to issuance of common stock from dividend reinvestment and stock incentive plans, net of forfeitures	24,149					188		27,901		(3,940)
Net proceeds from issuance of common stock	788,334					11,828		776,506
Conversion of preferred stock	0			(5)				5
Dividends paid:
Common stock dividends	(1,300,141)														(1,300,141)
Preferred stock dividends	(46,704)														(46,704)
Balances at end of period at Dec. 31, 2018	15,586,599			718,498		384,465		18,424,662		(68,499)		6,121,534			(10,818,557)		(129,769)		954,265
Comprehensive income:
Net income (loss)	1,299,797											1,232,432							67,365
Other comprehensive income (loss)	31,052																17,612		13,440
Total comprehensive income	1,330,849
Net change in noncontrolling interests	65,304							3,583											(68,887)
Amounts related to issuance of common stock from dividend reinvestment and stock incentive plans, net of forfeitures	14,869					162		25,163		(10,456)
Net proceeds from issuance of common stock	1,044,591					13,666		1,030,925
Conversion of preferred stock	0			(718,498)		12,712		705,786
Dividends paid:
Common stock dividends	(1,404,977)														(1,404,977)
Balances at end of period at Dec. 31, 2019	16,506,627	$ (5,212)	$ 16,501,415	0	$ 0	411,005	$ 411,005	20,190,119	$ 20,190,119	(78,955)	$ (78,955)	7,353,966	$ (5,212)	$ 7,348,754	(12,223,534)	$ (12,223,534)	(112,157)	$ (112,157)	966,183	$ 966,183
Comprehensive income:
Net income (loss)	1,077,754											978,844							98,910
Other comprehensive income (loss)	(30,854)																(36,347)		5,493
Total comprehensive income	1,046,900
Net change in noncontrolling interests	(143,575)							18,158											(161,733)
Amounts related to issuance of common stock from dividend reinvestment and stock incentive plans, net of forfeitures	10,409					622		27,666		(17,879)
Net proceeds from issuance of common stock	594,266					7,064		587,202
Repurchase of common stock	(7,656)									(7,656)
Dividends paid:
Common stock dividends	(1,120,187)														(1,120,187)
Balances at end of period at Dec. 31, 2020	$ 16,881,572			$ 0		$ 418,691		$ 20,823,145		$ (104,490)		$ 8,327,598			$ (13,343,721)		$ (148,504)		$ 908,853