Variable Interest Entities (VIEs) (Details) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2018 USD ($) variable_interest_entity entities MW	Dec. 31, 2017 USD ($) variable_interest_entity	Dec. 31, 2007 USD ($)
Variable Interest Entity [Line Items]
Total number of consolidated variable interest entities | variable_interest_entity	28
Investment in equity method investees	$ 6,774	$ 2,321
NEP OpCo [Member]
Variable Interest Entity [Line Items]
Total number of consolidated variable interest entities | variable_interest_entity		1
Carrying amount of assets, consolidated variable interest entity		$ 8,400
Carrying amount of liabilities, consolidated variable interest entity		6,200
Other variable interest entities [Member]
Variable Interest Entity [Line Items]
Investments in special purpose entities	2,653	2,634
FPL [Member] | Bankruptcy remote special purpose subsidiary [Member]
Variable Interest Entity [Line Items]
Carrying amount of assets, consolidated variable interest entity	107	148
Carrying amount of liabilities, consolidated variable interest entity	108	147
FPL [Member] | Other variable interest entities [Member]
Variable Interest Entity [Line Items]
Investments in special purpose entities	$ 2,176	2,195
NextEra Energy Resources [Member]
Variable Interest Entity [Line Items]
Total number of consolidated variable interest entities | variable_interest_entity	27
NextEra Energy Resources [Member] | Gas and/or oil variable interest entities [Member]
Variable Interest Entity [Line Items]
Total number of consolidated variable interest entities | variable_interest_entity	1
Carrying amount of assets, consolidated variable interest entity	$ 68	89
Carrying amount of liabilities, consolidated variable interest entity	$ 22	29
Natural gas and or oil electric generating facility capacity (in megawatts) | MW	110
NextEra Energy Resources [Member] | Photovoltaic Solar Facility [Member]
Variable Interest Entity [Line Items]
Total number of consolidated variable interest entities | variable_interest_entity	2
Ownership percentage	50.00%
Number of entities with ownership interest contributed | entities	3
Solar generating facility capability (in MW) | MW	277
Wind electric generating facility capability (in megawatts) | MW	374
NextEra Energy Resources [Member] | Wind variable interest entities [Member]
Variable Interest Entity [Line Items]
Total number of consolidated variable interest entities | variable_interest_entity	24
Carrying amount of assets, consolidated variable interest entity	$ 9,900	13,100
Carrying amount of liabilities, consolidated variable interest entity	$ 1,300	6,900
Wind electric generating facility capability (in megawatts) | MW	6,367
Indirect Subsidiary of NextEra Energy Resources [Member] | Photovoltaic Solar Facility [Member]
Variable Interest Entity [Line Items]
Carrying amount of assets, consolidated variable interest entity	$ 546	548
Carrying amount of liabilities, consolidated variable interest entity	569	594
NEECH [Member] | Special Purpose Entity that has Insufficient Equity at Risk [Member]
Variable Interest Entity [Line Items]
Carrying amount of assets, consolidated variable interest entity		490
Carrying amount of liabilities, consolidated variable interest entity		502
Other Investments [Member]
Variable Interest Entity [Line Items]
Investment in equity method investees	4,797	$ 248
Senior Secured Debt [Member] | FPL [Member] | Bankruptcy remote special purpose subsidiary [Member]
Variable Interest Entity [Line Items]
Storm-recovery bonds aggregate principal amount issued			$ 652
Proceeds from issuance of storm-recovery bonds			$ 644
NEP OpCo [Member]
Variable Interest Entity [Line Items]
Ownership percentage		65.10%
Subsidiaries of NEE [Member]
Variable Interest Entity [Line Items]
Additional commitments to invest	$ 70	$ 75
Additional VIEs committed to invest in | variable_interest_entity	3