CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (USD $) In Millions, except Share data, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Unearned ESOP Compensation [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total Common Shareholders' Equity Parent [Member]	Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2013	$ 18,040	$ 4	$ 6,437	$ (26)	$ 56	$ 11,569	$ 18,040	$ 0
Beginning Balance (in shares) at Dec. 31, 2013		435,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	430					430	430
Issuances of common stock, net of issuance cost of less than $1			13	1			14
Exercise of stock options and other incentive plan activity (in shares)		1,000,000
Exercise of stock options and other incentive plan activity			13				13
Dividends on common stock						(315)	(315)
Earned compensation under ESOP			11	2			13
Other comprehensive loss	(35)				(35)		(35)
Ending Balance at Mar. 31, 2014	18,160	4	6,474	(23)	21	11,684	18,160	0
Ending Balance (in shares) at Mar. 31, 2014		436,000,000
Beginning Balance at Dec. 31, 2014	20,168	4	7,193	(14)	(40)	12,773	19,916	252
Beginning Balance (in shares) at Dec. 31, 2014	443,000,000	443,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	650					650	650
Issuances of common stock, net of issuance cost of less than $1			13	1			14
Exercise of stock options and other incentive plan activity (in shares)		1,000,000
Exercise of stock options and other incentive plan activity			2				2
Dividends on common stock						(341)	(341)
Earned compensation under ESOP			10	1			11
Other comprehensive loss	(36)				(33)		(33)	(3)
Sale of NEER assets to NEP			16				16	(11)
Distributions to noncontrolling interests								(4)
Other changes in noncontrolling interests in subsidiaries								(5)
Ending Balance at Mar. 31, 2015	$ 20,464	$ 4	$ 7,234	$ (12)	$ (73)	$ 13,082	$ 20,235	$ 229
Ending Balance (in shares) at Mar. 31, 2015	444,000,000	444,000,000