Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ 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
Condensed consolidated quarterly financial information [Abstract]
Operating revenues	$ 4,010	$ 4,808	$ 4,404	$ 3,972	$ 3,699	$ 4,805	$ 3,817	$ 3,835	$ 17,195		$ 16,155		$ 17,486
Operating income	236	1,399	1,285	2,405	926	1,279	1,169	1,234	5,326		4,608		4,632
Net income	2,068	856	804	1,591	1,017	789	544	654	5,320		3,005		2,762
Net income (loss) attributable to NEE	$ 2,155	$ 847	$ 793	$ 1,583	$ 966	$ 753	$ 540	$ 653	$ 5,378		$ 2,912		$ 2,752
Basic EPS - Net income (in dollars per share)	$ 4.58	$ 1.80	$ 1.69	$ 3.39	$ 2.07	$ 1.63	$ 1.17	$ 1.42	$ 11.47		$ 6.29		$ 6.11
Diluted EPS - Net income (in dollars per share)	4.55	1.79	1.68	3.37	2.06	1.62	1.16	1.41	11.38		6.25		6.06
Dividends per share of common stock (in dollars per share)	0.9825	0.9825	0.9825	0.9825	0.870	0.87	0.87	0.87	$ 3.93		$ 3.48		$ 3.08
High common stock sales price (in dollars per share)	159.40	151.60	144.87	133.28	128.46	131.98	130.43	119.37
Low common stock sales price (in dollars per share)	$ 145.62	$ 138.00	$ 127.09	$ 117.33	$ 110.49	$ 120.22	$ 112.44	$ 102.20
FPL[Member]
Condensed consolidated quarterly financial information [Abstract]
Operating revenues	$ 2,877	$ 3,477	$ 3,091	$ 2,527	$ 2,558	$ 3,283	$ 2,750	$ 2,303	$ 11,972		$ 10,895		$ 11,651
Operating income	618	1,022	941	811	694	921	828	714	3,391		3,158		2,977
Net income (loss) attributable to NEE	$ 344	$ 566	$ 526	$ 445	$ 371	$ 515	$ 448	$ 393	$ 1,880	[1]	$ 1,727	[1]	$ 1,648	[1]

[1] FPL's comprehensive income is the same as reported net income