Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Thousands, shares in Millions		Total	Preferred Units [Member]	Preferred Partner [Member]	Units [Member]	Limited Partners [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Non-controlling Interests [Member]	Common Stock [Member]
Beginning balance, units at Dec. 31, 2018			14.0		56.1
Beginning balance at Dec. 31, 2018		$ 5,538,000		$ 548,000		$ 1,804,000	$ (6,000)	$ 3,192,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common units (in units)					0.1
Issuance of common units - net		1,000				1,000
Net income (loss)		(121,000)		6,000		(22,000)		(105,000)
Other comprehensive income (loss)		(5,000)					(2,000)	(3,000)
Related party contributions		1,000						1,000
Related party distributions		(51,000)						(51,000)
Other differential membership investment activity		24,000						24,000
Changes in non-economic ownership interests		(6,000)						(6,000)
Payments to Class B noncontrolling interests investors		(5,000)						(5,000)
Distributions to unitholders	[1]	(32,000)		(6,000)		(26,000)
Other		1,000						1,000
Ending balance, units at Mar. 31, 2019			14.0		56.2
Ending balance at Mar. 31, 2019		5,345,000		548,000		1,757,000	(8,000)	3,048,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Distributions per common unit (usd per share)									$ 0.4650
Beginning balance, units at Dec. 31, 2018			14.0		56.1
Beginning balance at Dec. 31, 2018		5,538,000		548,000		1,804,000	(6,000)	3,192,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(244,000)
Other comprehensive income (loss)		(5,000)
Ending balance, units at Jun. 30, 2019			14.0		56.2
Ending balance at Jun. 30, 2019		6,500,000		548,000		1,704,000	(8,000)	4,256,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accrued preferred distributions		6,000
Beginning balance, units at Mar. 31, 2019			14.0		56.2
Beginning balance at Mar. 31, 2019		5,345,000		548,000		1,757,000	(8,000)	3,048,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common units - net		1,000				1,000
Acquisition of subsidiaries with noncontrolling ownership interests		472,000						472,000
Net income (loss)		(124,000)		6,000		(28,000)		(102,000)
Other comprehensive income (loss)		0
Related party note receivable		1,000						1,000
Related party contributions		11,000						11,000
Related party distributions		(56,000)						(56,000)
Other differential membership investment activity		(8,000)						(8,000)
Payments to Class B noncontrolling interests investors		(3,000)						(3,000)
Sale of Class B noncontrolling interest - net		893,000						893,000
Distributions to unitholders	[1]	(33,000)		(6,000)		(27,000)
Other		1,000				1,000
Ending balance, units at Jun. 30, 2019			14.0		56.2
Ending balance at Jun. 30, 2019		$ 6,500,000		548,000		1,704,000	(8,000)	4,256,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Distributions per common unit (usd per share)									0.4825
Beginning balance, units at Dec. 31, 2019		65.5	4.7		65.5
Beginning balance at Dec. 31, 2019		$ 7,066,000		183,000		2,008,000	(8,000)	4,883,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(720,000)		2,000		(222,000)		(500,000)
Other comprehensive income (loss)		0
Related party contributions		3,000						3,000
Related party distributions		(62,000)						(62,000)
Other differential membership investment activity		40,000						40,000
Payments to Class B noncontrolling interests investors		(10,000)						(10,000)
Distributions to unitholders	[2]	(37,000)		(2,000)		(35,000)
Other		(1,000)				(1,000)		0
Ending balance, units at Mar. 31, 2020			4.7		65.5
Ending balance at Mar. 31, 2020		$ 6,279,000		183,000		1,750,000	(8,000)	4,354,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Distributions per common unit (usd per share)									0.5350
Beginning balance, units at Dec. 31, 2019		65.5	4.7		65.5
Beginning balance at Dec. 31, 2019		$ 7,066,000		183,000		2,008,000	(8,000)	4,883,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(593,000)
Other comprehensive income (loss)		$ 1,000
Ending balance, units at Jun. 30, 2020		65.5	4.7		65.5
Ending balance at Jun. 30, 2020		$ 6,283,000		183,000		1,759,000	(8,000)	4,349,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Accrued preferred distributions		2,000
Beginning balance, units at Mar. 31, 2020			4.7		65.5
Beginning balance at Mar. 31, 2020		6,279,000		183,000		1,750,000	(8,000)	4,354,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		127,000		2,000		47,000		78,000
Other comprehensive income (loss)		1,000						1,000
Related party note receivable		1,000						1,000
Related party contributions		2,000						2,000
Related party distributions		(69,000)						(69,000)
Other differential membership investment activity		(8,000)						(8,000)
Payments to Class B noncontrolling interests investors		(11,000)						(11,000)
Distributions to unitholders	[2]	(38,000)		(2,000)		(36,000)
Other		$ (1,000)				(2,000)		1,000
Ending balance, units at Jun. 30, 2020		65.5	4.7		65.5
Ending balance at Jun. 30, 2020		$ 6,283,000		$ 183,000		$ 1,759,000	$ (8,000)	$ 4,349,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Distributions per common unit (usd per share)									$ 0.5550

[1] Distributions per common unit of $0.4825 and $0.4650 were paid during the three months ended June 30, 2019 and March 31, 2019, respectively.

[2] Distributions per common unit of $0.5550 and $0.5350 were paid during the three months ended June 30, 2020 and March 31, 2020, respectively. At June 30, 2020, $2 million of preferred unit distributions were accrued and are payable in August 2020.