Commitments and Contingencies (Required Capacity and/or Minimum Payments Under Contracts) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Corporate and Other [Member]
Long-term Purchase Commitment [Line Items]
Capacity payments and/or minimum payments - 2019	$ 45
Capacity payments and/or minimum payments - 2020	30
Capacity payments and/or minimum payments - 2021	15
Capacity payments and/or minimum payments - 2022	10
Capacity payments and/or minimum payments - 2023	5
Capacity payments and/or minimum payments - Thereafter	0
Commitment to invest	55
Joint obligations due in the next year	20
FPL[Member]
Long-term Purchase Commitment [Line Items]
Capacity payments and/or minimum payments - 2019	985
Capacity payments and/or minimum payments - 2020	990
Capacity payments and/or minimum payments - 2021	985
Capacity payments and/or minimum payments - 2022	970
Capacity payments and/or minimum payments - 2023	960
Capacity payments and/or minimum payments - Thereafter	11,495
Related Party Transaction, Amounts of Transaction	303	$ 160
FPL[Member] | Natural Gas Including Transportation and Storage Contract Minimum Payments [Member] | Sabal Trail and Florida Southeast Connection [Member]
Long-term Purchase Commitment [Line Items]
Capacity payments and/or minimum payments - 2019	320
Capacity payments and/or minimum payments - 2020	385
Capacity payments and/or minimum payments - 2021	415
Capacity payments and/or minimum payments - 2022	415
Capacity payments and/or minimum payments - 2023	410
Capacity payments and/or minimum payments - Thereafter	7,175
NEER [Member]
Long-term Purchase Commitment [Line Items]
Capacity payments and/or minimum payments - 2019	2,215
Capacity payments and/or minimum payments - 2020	390
Capacity payments and/or minimum payments - 2021	170
Capacity payments and/or minimum payments - 2022	185
Capacity payments and/or minimum payments - 2023	105
Capacity payments and/or minimum payments - Thereafter	1,365
NEER [Member] | Mountain Valley Pipeline [Member]
Long-term Purchase Commitment [Line Items]
Capacity payments and/or minimum payments - 2019	15
Capacity payments and/or minimum payments - 2020	65
Capacity payments and/or minimum payments - 2021	65
Capacity payments and/or minimum payments - 2022	65
Capacity payments and/or minimum payments - 2023	65
Capacity payments and/or minimum payments - Thereafter	1,020
NEER [Member] | Contract Group 1 [Member]
Long-term Purchase Commitment [Line Items]
Commitment amount included in capital expenditures	$ 2,700
Join Venture [Member] | NEER [Member]
Long-term Purchase Commitment [Line Items]
Ownership interest	31.00%
Consolidation, Eliminations [Member] | FPL[Member]
Long-term Purchase Commitment [Line Items]
Related Party Transaction, Amounts of Transaction	$ 95	$ 45