Condensed Consolidated Statement of Equity - USD ($)	Total	At the Market Program [Member]	Stockholders' Equity, Total [Member]		Stockholders' Equity, Total [Member] At the Market Program [Member]	Common Stock [Member]	Common Stock [Member] At the Market Program [Member]	4.50% Convertible Preferred Stock	6.875% Convertible Preferred Stock	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] At the Market Program [Member]	Accumulated Foreign Currency Adjustment Attributable to Parent [Member]		Dividends/Distributions in Excess of Earnings [Member]
Balance, shares Period Start at Dec. 31, 2015						333,771,660
Balance, value Period Start at Dec. 31, 2015			$ 7,089,221,000			$ 3,338,000		$ 98,000	$ 0	$ 9,548,580,000		$ (4,398,000)		$ (2,458,397,000)
Preferred Stock, Shares Outstanding Period Start at Dec. 31, 2015								9,775,000	0
Stock-based compensation related activity, net of forfeitures, value			67,262,000			$ 2,000				67,260,000		0		0
Stock-based compensation related activity, net of forfeitures, shares						257,720
Purchases and retirement of capital stock, value			(24,759,000)			$ (3,000)				(24,756,000)		0		0
Stock Issued During Period, Shares, New Issues						0	3,828,064
Proceeds from Issuance of Convertible Preferred Stock	$ 0
Stock Issued During Period, Value, New Issues						$ 0				0
Proceeds from Issuance of Common Stock	323,798,000				$ 323,798,000		$ 38,000				$ 323,760,000
Purchases and retirement of capital stock, shares						(287,513)
Other comprehensive income (loss)	(1,143,000)		(1,143,000)	[1]		$ 0				0		(1,143,000)	[1]	0
Common stock dividends/distributions			(899,934,000)											(899,934,000)
Preferred stock dividends	(32,991,000)		(32,991,000)											(32,991,000)
Net income (loss)	232,263,000		232,263,000			$ 0				0		0		232,263,000
Balance, shares Period End at Sep. 30, 2016						337,569,931
Balance, value Period End at Sep. 30, 2016			6,753,717,000			$ 3,375,000		$ 98,000	$ 0	9,914,844,000		(5,541,000)		(3,159,059,000)
Preferred Stock, Shares Outstanding Period End at Sep. 30, 2016								9,775,000	0
Balance, shares Period Start at Jun. 30, 2016						337,562,378
Balance, value Period Start at Jun. 30, 2016			6,948,307,000			$ 3,375,000		$ 98,000		9,894,921,000		(4,006,000)		(2,946,081,000)
Preferred Stock, Shares Outstanding Period Start at Jun. 30, 2016								9,775,000
Stock-based compensation related activity, net of forfeitures, value			20,222,000			$ 0				20,222,000		0		0
Stock-based compensation related activity, net of forfeitures, shares						10,784
Purchases and retirement of capital stock, value			(299,000)			$ 0				(299,000)		0		0
Purchases and retirement of capital stock, shares						(3,231)
Other comprehensive income (loss)	(1,535,000)		(1,535,000)	[1]		$ 0				0		(1,535,000)	[1]	0
Common stock dividends/distributions			(300,347,000)											(300,347,000)
Preferred stock dividends	(10,997,000)		(10,997,000)											(10,997,000)
Net income (loss)	$ 98,366,000		98,366,000			$ 0				0		0		98,366,000
Balance, shares Period End at Sep. 30, 2016						337,569,931
Balance, value Period End at Sep. 30, 2016			6,753,717,000			$ 3,375,000		$ 98,000	$ 0	9,914,844,000		(5,541,000)		(3,159,059,000)
Preferred Stock, Shares Outstanding Period End at Sep. 30, 2016								9,775,000	0
Balance, shares Period Start at Dec. 31, 2016	360,536,659					360,536,659
Balance, value Period Start at Dec. 31, 2016	$ 7,557,115,000		7,557,115,000			$ 3,605,000		$ 0	$ 0	10,938,236,000		(5,888,000)		(3,378,838,000)
Preferred Stock, Shares Outstanding Period Start at Dec. 31, 2016	0							0	0
Stock-based compensation related activity, net of forfeitures, value			75,489,000			$ 7,000				75,482,000		0		0
Stock-based compensation related activity, net of forfeitures, shares						739,805
Purchases and retirement of capital stock, value			(23,037,000)			$ (3,000)				(23,034,000)		0		0
Stock Issued During Period, Shares, New Issues						45,255,158	242,300		1,650,000
Proceeds from Issuance of Convertible Preferred Stock	$ 1,607,759,000		1,607,759,000						$ 17,000	1,607,742,000
Proceeds from Issuance of Common Stock	4,220,766,000	$ 22,009,000	4,220,766,000			$ 454,000				4,220,312,000
Purchases and retirement of capital stock, shares						(256,820)
Other comprehensive income (loss)	929,000		929,000	[1]		$ 0				0		929,000	[1]	0
Common stock dividends/distributions			(1,083,200,000)											(1,083,200,000)
Preferred stock dividends	(29,935,000)		(29,935,000)											(29,935,000)
Net income (loss)	$ 346,446,000		346,446,000			$ 0				0		0		346,446,000
Balance, shares Period End at Sep. 30, 2017	406,274,802					406,274,802
Balance, value Period End at Sep. 30, 2017	$ 12,672,332,000		12,672,332,000			$ 4,063,000		$ 0	$ 17,000	16,818,738,000		(4,959,000)		(4,145,527,000)
Preferred Stock, Shares Outstanding Period End at Sep. 30, 2017	1,650,000							0	1,650,000
Balance, shares Period Start at Jun. 30, 2017						366,115,800
Balance, value Period Start at Jun. 30, 2017			7,590,309,000			$ 3,661,000		$ 0	$ 0	11,433,018,000		(5,183,000)		(3,841,187,000)
Preferred Stock, Shares Outstanding Period Start at Jun. 30, 2017								0	0
Stock-based compensation related activity, net of forfeitures, value			22,079,000			$ 0				22,079,000		0		0
Stock-based compensation related activity, net of forfeitures, shares						13,261
Purchases and retirement of capital stock, value			(443,000)			$ 0				(443,000)		0		0
Stock Issued During Period, Shares, New Issues						40,150,000			1,650,000
Proceeds from Issuance of Convertible Preferred Stock			1,607,759,000						$ 17,000	1,607,742,000
Proceeds from Issuance of Common Stock			3,756,744,000			$ 402,000				3,756,342,000
Purchases and retirement of capital stock, shares						(4,259)
Other comprehensive income (loss)	$ 224,000		224,000	[1]		$ 0				0		224,000	[1]	0
Common stock dividends/distributions			(389,599,000)											(389,599,000)
Preferred stock dividends	(29,935,000)		(29,935,000)											(29,935,000)
Net income (loss)	$ 115,194,000		115,194,000			$ 0				0		0		115,194,000
Balance, shares Period End at Sep. 30, 2017	406,274,802					406,274,802
Balance, value Period End at Sep. 30, 2017	$ 12,672,332,000		$ 12,672,332,000			$ 4,063,000		$ 0	$ 17,000	$ 16,818,738,000		$ (4,959,000)		$ (4,145,527,000)
Preferred Stock, Shares Outstanding Period End at Sep. 30, 2017	1,650,000							0	1,650,000

[1] See the condensed statement of operations and other comprehensive income (loss) for the components of "other comprehensive income (loss)."