CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total Common Shareholders' Equity Parent [Member]	Noncontrolling Interest [Member]
Beginning Balance (in shares) at Dec. 31, 2015		461
Beginning Balance at Dec. 31, 2015	$ 23,112	$ 5	$ 8,596	$ (167)	$ 14,140	$ 22,574	$ 538
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	1,198				1,193	1,193	5
Issuances of common stock, net of issuance cost of less than $1 (in shares)		0
Issuances of common stock, net of issuance cost of less than $1		$ 0	16			16
Share-based payment activity (in shares)		1
Share-based payment activity			64			64
Dividends on common stock					(803)	(803)
Other comprehensive income (loss)	72			85		85	(13)
Sale of NEER assets to NEP			27			27	199
Distributions to noncontrolling interests							(23)
Other			0		18	18	2
Ending Balance (in shares) at Jun. 30, 2016		462
Ending Balance at Jun. 30, 2016	$ 23,882	$ 5	8,703	(82)	14,548	23,174	708
Beginning Balance (in shares) at Dec. 31, 2016	468	468
Beginning Balance at Dec. 31, 2016	$ 25,331	$ 5	8,948	(70)	15,458	24,341	990
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	2,395				2,376	2,376	19
Issuances of common stock, net of issuance cost of less than $1 (in shares)		1
Issuances of common stock, net of issuance cost of less than $1			15			15
Share-based payment activity (in shares)		0
Share-based payment activity			44			44
Dividends on common stock					(920)	(920)
Other comprehensive income (loss)	$ 85			73		73	12
Sale of NEER assets to NEP			0			0	(17)
Distributions to noncontrolling interests							(39)
Other			(3)			(3)	(15)
Ending Balance (in shares) at Jun. 30, 2017	469	469
Ending Balance at Jun. 30, 2017	$ 26,876	$ 5	$ 9,004	$ 3	$ 16,914	$ 25,926	$ 950