Debt (Schedule of Debt Instruments) (Details) $ in Millions	12 Months Ended
Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Less current maturities of long-term debt	$ 1,676	$ 2,604
Long-term debt, excluding current maturities	31,463	27,818
Variable rate tax exempt bonds	838
liabilities associated with assets held-for-sale [Member]
Debt Instrument [Line Items]
Total long-term debt	373	373
FPL[Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs and discount	(105)	(108)
Total long-term debt	11,702	10,072
Less current maturities of long-term debt	466	367
Long-term debt, excluding current maturities	11,236	9,705
FPL[Member] \| First mortgage bonds - fixed [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 9,145	$ 8,690
Weighted-average interest rate	4.70%	4.78%
FPL[Member] \| Storm-recovery bonds - fixed [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 144	$ 210
Weighted-average interest rate	5.26%	5.26%
FPL[Member] \| Pollution control, solid waste disposal and industrial development revenue bonds - variable [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 966	$ 778
Weighted-average interest rate	2.12%	0.77%
FPL[Member] \| Other long-term debt - variable [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 1,501	$ 450
Weighted-average interest rate	2.01%	1.66%
FPL[Member] \| Other long-term debt - fixed [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 51	$ 52
Weighted-average interest rate	5.10%	5.09%
Capital Holdings [Member]
Debt Instrument [Line Items]
Fair value hedge adjustment	$ 1	$ 8
Unamortized debt issuance costs and discount	(94)	(101)
Total long-term debt	11,256	11,206
Less current maturities of long-term debt	645	1,724
Long-term debt, excluding current maturities	10,611	9,482
Capital Holdings [Member] \| Other long-term debt - variable [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 52	$ 60
Weighted-average interest rate	2.58%	1.77%
Capital Holdings [Member] \| Other long-term debt - fixed [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 920	$ 924
Weighted-average interest rate	2.46%	2.45%
Capital Holdings [Member] \| Debentures - fixed [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 4,100	$ 4,100
Weighted-average interest rate	3.00%	2.87%
Capital Holdings [Member] \| Debentures, related to NEE's equity units - fixed [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 2,200	$ 2,200
Weighted-average interest rate	1.88%	1.88%
Capital Holdings [Member] \| Junior subordinated debentures - primarily fixed [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 3,456	$ 3,460
Weighted-average interest rate	4.79%	5.40%
Capital Holdings [Member] \| Japanese yen denominated senior notes - fixed [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 89	$ 85
Weighted-average interest rate	5.13%	5.13%
Capital Holdings [Member] \| Japanese yen denominated term loans - variable [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 532	$ 470
Weighted-average interest rate	2.76%	1.83%
NEER [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs and premium - net	$ (181)	$ (168)
Total long-term debt	10,181	9,144
Less current maturities of long-term debt	565	513
Long-term debt, excluding current maturities	9,616	8,631
NEER [Member] \| Senior secured limited-recourse bonds and notes - fixed [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 2,114	$ 2,091
Weighted-average interest rate	5.74%	6.00%
NEER [Member] \| Senior secured limited-recourse term loans - primarily variable [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 5,165	$ 4,959
Weighted-average interest rate	3.32%	2.78%
NEER [Member] \| Senior Unsecured Notes - Fixed [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 1,100	$ 0
Weighted-average interest rate	4.38%
NEER [Member] \| Senior Unsecured NEP Convertible Notes - Fixed [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 300	0
Weighted-average interest rate	1.50%
NEER [Member] \| Other long-term debt - primarily variable [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 1,683	$ 2,262
Weighted-average interest rate	3.29%	2.97%
Wholly-Owned Subsidiary of NEER [Member]
Debt Instrument [Line Items]
Debt collateralized by third party note receivable	$ 483	$ 490
NEP [Member]
Debt Instrument [Line Items]
Debt conversion, converted instrument, rate	0.018917

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