Summary of Significant Accounting and Reporting Policies - Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balances, beginning of period		$ 4,883,000			$ 4,883,000
Related party note receivable	$ 1,000		$ 1,000
Sale of noncontrolling interest in a NEP OpCo subsidiary			893,000
Net income (loss) attributable to NCI	78,000		(102,000)		(421,000)	$ (207,000)
Related party contributions	2,000	3,000	11,000	$ 1,000
Related party distributions	(69,000)	(62,000)	(56,000)	(51,000)
Changes in non-economic ownership interests				(6,000)
Differential membership investment contributions, net of distributions			472,000
Payments to Class B noncontrolling interests investors	(11,000)	(10,000)	(3,000)	(5,000)
Other	(1,000)	(1,000)	1,000	1,000
Balances, end of period	4,349,000				4,349,000
Class B Noncontrolling Ownership Interests [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balances, beginning of period	2,670,000	2,628,000	758,000	751,000	2,628,000	751,000
Sale of noncontrolling interest in a NEP OpCo subsidiary			893,000
Net income (loss) attributable to NCI	53,000	52,000	25,000	12,000
Payments to Class B noncontrolling interests investors	(11,000)	(10,000)	(3,000)	(5,000)
Balances, end of period	2,712,000	2,670,000	1,673,000	758,000	2,712,000	1,673,000
Differential Membership Interests [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balances, beginning of period	1,767,000	1,798,000	1,983,000	2,019,000	1,798,000	2,019,000
Net income (loss) attributable to NCI	(78,000)	(71,000)	(63,000)	(60,000)
Differential membership investment contributions, net of distributions	(8,000)	40,000	(8,000)	24,000
Balances, end of period	1,681,000	1,767,000	1,912,000	1,983,000	1,681,000	1,912,000
NEER's Noncontrolling Ownership Interests in NEP OpCo and Silver State [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balances, beginning of period	(130,000)	389,000	241,000	342,000	389,000	342,000
Related party note receivable	1,000		1,000
Acquisition of subsidiaries with differential membership interests			472,000
Net income (loss) attributable to NCI	97,000	(459,000)	(59,000)	(50,000)
Other comprehensive income (loss)	1,000			(3,000)
Related party contributions			11,000	1,000
Related party distributions	(67,000)	(60,000)	(54,000)	(50,000)
Other	1,000			1,000
Balances, end of period	(97,000)	(130,000)	612,000	241,000	(97,000)	612,000
Other Noncontrolling Interest [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balances, beginning of period	47,000	68,000	66,000	80,000	68,000	80,000
Net income (loss) attributable to NCI	6,000	(22,000)	(5,000)	(7,000)
Other comprehensive income (loss)	0			0
Related party contributions	2,000	3,000
Related party distributions	(2,000)	(2,000)	(2,000)	(1,000)
Changes in non-economic ownership interests				(6,000)
Balances, end of period	53,000	47,000	59,000	66,000	53,000	59,000
Non-controlling Interests [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Balances, beginning of period	4,354,000	4,883,000	3,048,000	3,192,000	4,883,000	3,192,000
Related party note receivable	1,000		1,000
Sale of noncontrolling interest in a NEP OpCo subsidiary			893,000
Acquisition of subsidiaries with differential membership interests			472,000
Net income (loss) attributable to NCI	78,000	(500,000)	(102,000)	(105,000)
Other comprehensive income (loss)	1,000			(3,000)
Related party contributions	2,000	3,000	11,000	1,000
Related party distributions	(69,000)	(62,000)	(56,000)	(51,000)
Changes in non-economic ownership interests				(6,000)
Differential membership investment contributions, net of distributions	(8,000)	40,000	(8,000)	24,000
Payments to Class B noncontrolling interests investors	(11,000)	(10,000)	(3,000)	(5,000)
Other	1,000			1,000
Balances, end of period	$ 4,349,000	$ 4,354,000	$ 4,256,000	$ 3,048,000	$ 4,349,000	$ 4,256,000