Equity (Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Reconciliation of basic and diluted earnings per share of common stock [Abstract]
Net income (loss) attributable to NEE	$ 4,428,000,000	$ 1,583,000,000	[1]
Adjustment for the impact of dilutive securities at NEP	(9,000,000)	0
Net income attributable to NEE - assuming dilution	$ 4,419,000,000	$ 1,583,000,000
Denominator:
Weighted-average number of common shares outstanding - basic	470.7	467.5	[1]
Equity units, stock options, performance share awards, forward sale agreements and restricted stock	3.6	2.7
Weighted-average number of common shares outstanding - assuming dilution	474.3	470.2	[1]
Earnings per share attributable to NEE:
Basic (in dollars per share)	$ 9.41	$ 3.39	[1]
Assuming dilution (in dollars per share)	$ 9.32	$ 3.37	[1]
Antidilutive securities (in shares)	0.2	11.9

[1] Prior period amounts have been retrospectively adjusted as discussed in Note 3 - Amendments to Presentation of Retirement Benefits.