Equity (Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of basic and diluted earnings per share of common stock [Abstract]
Net income (loss) attributable to NEE	$ 2,155	$ 847	$ 793	$ 1,583	$ 966	$ 753	$ 540	$ 653	$ 5,378	$ 2,912	$ 2,752
Denominator:
Weighted-average number of common shares outstanding - basic									468.8	463.1	450.5
Equity units, stock options, performance share awards, forward sale agreements and restricted stock(a)									3.7	2.7	3.5
Weighted-average number of common shares outstanding - assuming dilution									472.5	465.8	454.0
Earnings per share attributable to NEE:
Basic	$ 4.58	$ 1.80	$ 1.69	$ 3.39	$ 2.07	$ 1.63	$ 1.17	$ 1.42	$ 11.47	$ 6.29	$ 6.11
Assuming dilution	$ 4.55	$ 1.79	$ 1.68	$ 3.37	$ 2.06	$ 1.62	$ 1.16	$ 1.41	$ 11.38	$ 6.25	$ 6.06