Debt (Narrative) (Details) - USD ($)	1 Months Ended
	Aug. 31, 2016	Sep. 30, 2015	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Weighted-average interest rate of commercial paper and short-tem borrowings (in hundredths)			1.68%	1.07%
Line of Credit [Member]
Debt Instrument [Line Items]
Available capacity			$ 9,900,000,000
Letter of Credit [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Available capacity			80,000,000
Revolving Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Available capacity			9,800,000,000
Revolving Credit Facility, Issuance of Letters of Credit [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Available capacity			$ 3,000,000,000
FPL[Member]
Debt Instrument [Line Items]
Weighted-average interest rate of commercial paper and short-tem borrowings (in hundredths)			1.68%	1.07%
FPL[Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Available capacity			$ 3,100,000,000
FPL[Member] | Letter of Credit [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Available capacity			0
FPL[Member] | Revolving Credit Facility [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Available capacity			3,100,000,000
FPL[Member] | Revolving Credit Facility, Issuance of Letters of Credit [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Available capacity			$ 700,000,000
NEE Equity Units 2015 [Member]
Sale of equity units [Abstract]
Amount of equity units sold		$ 700,000,000
Stated amount of each equity unit (in dollars per share)		$ 50
Undivided beneficial ownership interest per debenture (in hundredths)		5.00%
Principal amount of each debenture		$ 1,000
Price per share of stock purchase contract - low range (in dollars per share)		$ 95.35
Price per share of stock purchase contract - high range (in dollars per share)		$ 114.42
Number of shares (subject to antidilution adjustments) if purchased on final settlement date at less than or equal to low range threshold (in shares)		0.5293
Number of shares (subject to antidilution adjustments) if purchased on the final settlement date at equal to or greater than high range threshold (in shares)		0.4412
Trading period (in days) over which the market value is determined by reference to the average closing prices of the common stock		20 days
Rate of total annual distributions on equity units (in hundredths)		6.371%
Interest rate		2.36%
Rate of payments on stock purchase contracts (in hundredths)		4.011%
NEE Equity Units 2016 [Member]
Sale of equity units [Abstract]
Amount of equity units sold	$ 1,500,000,000
Stated amount of each equity unit (in dollars per share)	$ 50
Undivided beneficial ownership interest per debenture (in hundredths)	5.00%
Principal amount of each debenture	$ 1,000
Number of shares (subject to antidilution adjustments) if purchased on final settlement date at less than or equal to low range threshold (in shares)	0.3931
Number of shares (subject to antidilution adjustments) if purchased on the final settlement date at equal to or greater than high range threshold (in shares)	0.3144
Trading period (in days) over which the market value is determined by reference to the average closing prices of the common stock	20 days
Rate of total annual distributions on equity units (in hundredths)	6.123%
Interest rate	1.65%
Rate of payments on stock purchase contracts (in hundredths)	4.473%
NEE Equity Units 2016 [Member] | Minimum [Member]
Sale of equity units [Abstract]
Price per share of stock purchase contract (in dollars per share)	$ 127.63
NEE Equity Units 2016 [Member] | Maximum [Member]
Sale of equity units [Abstract]
Price per share of stock purchase contract (in dollars per share)	$ 159.54