Summarized Financial Information of NEECH - Income Statement (Details) - USD ($) $ 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
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 expenses - net									(11,869)	(11,547)	(12,854)
Interest expense									(1,558)	(1,093)	(1,211)
Equity in earnings of subsidiaries									0	0	0
Other income - net									899	873	569
Income (loss) before income taxes									4,667	4,388	3,990
Income tax expense (benefit)									(653)	1,383	1,228
Net income (loss)	2,068	856	804	1,591	1,017	789	544	654	5,320	3,005	2,762
LESS NET INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTERESTS									(58)	93	10
Net income (loss) attributable to NEE	$ 2,155	$ 847	$ 793	$ 1,583	$ 966	$ 753	$ 540	$ 653	5,378	2,912	2,752
Reportable Legal Entities [Member] | NEE (Guarantor) [Member]
Operating revenues									0	0	0
Operating expenses - net									(25)	(20)	(17)
Interest expense									(3)	(1)	(4)
Equity in earnings of subsidiaries									5,391	2,956	2,754
Other income - net									2	5	1
Income (loss) before income taxes									5,365	2,940	2,734
Income tax expense (benefit)									(14)	28	(18)
Net income (loss)									5,379	2,912	2,752
LESS NET INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTERESTS									0	0	0
Net income (loss) attributable to NEE									$ 5,379	2,912	2,752
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Ownership interest	100.00%								100.00%
Operating revenues									$ 5,322	5,283	5,849
Operating expenses - net									(3,293)	(3,663)	(4,142)
Interest expense									(1,073)	(636)	(764)
Equity in earnings of subsidiaries									0	0	0
Other income - net									845	793	498
Income (loss) before income taxes									1,801	1,777	1,441
Income tax expense (benefit)									(1,712)	354	299
Net income (loss)									3,513	1,423	1,142
LESS NET INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTERESTS									(58)	93	10
Net income (loss) attributable to NEE									3,571	1,330	1,132
Consolidation, Eliminations [Member]
Operating revenues									11,873	10,872	11,637
Operating expenses - net									(8,551)	(7,864)	(8,695)
Interest expense									(482)	(456)	(443)
Equity in earnings of subsidiaries									(5,391)	(2,956)	(2,754)
Other income - net									52	75	70
Income (loss) before income taxes									(2,499)	(329)	(185)
Income tax expense (benefit)									1,073	1,001	947
Net income (loss)									(3,572)	(1,330)	(1,132)
LESS NET INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTERESTS									0	0	0
Net income (loss) attributable to NEE									$ (3,572)	$ (1,330)	$ (1,132)