Acquisitions (Details) $ in Millions			1 Months Ended
	Jul. 16, 2019 USD ($) mi	Jan. 01, 2019 USD ($) customer county mi MW	Dec. 31, 2018 USD ($)	Sep. 30, 2019 USD ($)
Business Acquisition [Line Items]
Goodwill			$ 891	$ 4,129
NextEra Energy Capital Holdings, Inc. (Consolidated) [Member] | Term Loan Agreements [Member]
Business Acquisition [Line Items]
Borrowings			$ 4,500
Trans Bay Cable, LLC [Member]
Business Acquisition [Line Items]
Number of miles of power lines | mi	53
Gulf Power [Member]
Business Acquisition [Line Items]
Cash purchase price		$ 4,470
Business combination, recognized identifiable assets acquired and liabilities assumed, noncurrent liabilities, long-term debt		1,300
Assets assumed		5,300
Property, plant and equipment		4,000
Regulatory assets		490
Assumed liabilities		3,400
Regulatory liabilities		640
Deferred income taxes		563
Goodwill		$ 2,600
Operating right-of-use assets				220
Lease liabilities				220
Expected lease payments over the remaining terms of the operating leases				235
Gulf Power [Member] | Gulf Power [Member]
Business Acquisition [Line Items]
Number of customers acquired (more than) | customer		460,000
Number of counties in which entity operates | county		8
Number of miles of power lines | mi		9,400
Electric generating facility capacity (in megawatts) | MW		2,300
Trans Bay Cable, LLC [Member]
Business Acquisition [Line Items]
Assets assumed	$ 710
Assumed liabilities	652
Goodwill	613
Goodwill, Expected Tax Deductible Amount				570
Operating right-of-use assets				145
Lease liabilities				145
Expected lease payments over the remaining terms of the operating leases				$ 445
Trans Bay Cable, LLC [Member] | NextEra Energy Transmission, LLC Subsidiary [Member]
Business Acquisition [Line Items]
Cash purchase price	671
Business combination, recognized identifiable assets acquired and liabilities assumed, noncurrent liabilities, long-term debt	$ 420