Consolidated Statements of Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Capital in Excess of Par Value	Treasury Stock	Cumulative Net Income	Cumulative Dividends	Accumulated Other Comprehensive Income (Loss)	Other Equity	Noncontrolling Interests
Balances at beginning of period at Dec. 31, 2014	$ 13,473,049	$ 1,006,250	$ 328,835	$ 14,740,712	$ (35,241)	$ 2,842,022	$ (5,635,923)	$ (77,009)	$ 5,507	$ 297,896
Comprehensive income:
Net income (loss)	540,049					536,074				3,975
Other comprehensive income	(13,610)							(4,661)		(8,949)
Total comprehensive income	526,439
Net change in noncontrolling interests	62,398			(2,786)						65,184
Amounts related to stock incentive plans, net of forfeitures	8,342		211	16,304	(6,452)				(1,721)
Proceeds from issuance of common stock	1,563,401		21,528	1,541,873
Equity component of convertible debt	5,815		1,077	4,738
Option compensation expense	452								452
Cash dividends paid:
Common stock	(561,914)						(561,914)
Preferred Stock	(32,703)						(32,703)
Balances at end of period at Jun. 30, 2015	15,045,279	1,006,250	351,651	16,300,841	(41,693)	3,378,096	(6,230,540)	(81,670)	4,238	358,106
Balances at beginning of period at Dec. 31, 2015	15,175,885	1,006,250	354,811	16,478,300	(44,372)	3,725,772	(6,846,056)	(88,243)	4,098	585,325
Comprehensive income:
Net income (loss)	380,236					377,147				3,089
Other comprehensive income	(59,200)							(71,395)		12,195
Total comprehensive income	321,036
Distributions to noncontrolling interests	(167,073)			(41,658)						(125,415)
Amounts related to stock incentive plans, net of forfeitures	25,727		688	32,284	(6,916)				(329)
Proceeds from issuance of common stock	158,711		2,451	156,260
Option compensation expense	148								148
Cash dividends paid:
Common stock	(613,163)						(613,163)
Preferred Stock	(32,703)						(32,703)
Balances at end of period at Jun. 30, 2016	$ 14,868,568	$ 1,006,250	$ 357,950	$ 16,625,186	$ (51,288)	$ 4,102,919	$ (7,491,922)	$ (159,638)	$ 3,917	$ 475,194