Fair Value Measurements (Fair Value of Instruments Recorded at Other Than Fair Value and Special Use Funds) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special use funds: nuclear decommissioning fund assets	$ 6,478		$ 6,478		$ 5,818
Special Use Funds Storm Fund Assets	69		69		68
Available for sale debt securities amortized cost	1,963		$ 1,963		1,994
Special Use Funds Nuclear Decommissioning Funds Weighted Average Maturity			8 years
Fair Value Assumptions, Expected Term			1 year
Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Fair Value Disclosure	956		$ 956		884
Other Investments Financial Instruments Primarily Notes Receivable Fair Value Disclosure	31		31		54
Long Term Debt Including Current Maturities Fair Value Disclosure	36,620		36,620		29,498
Estimated Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Fair Value Disclosure	955		955		883
Other Investments Financial Instruments Primarily Notes Receivable Fair Value Disclosure	31		31		54
Long Term Debt Including Current Maturities Fair Value Disclosure	39,158		39,158		30,043
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special use funds: nuclear decommissioning fund assets	4,438		4,438		3,987
Special Use Funds Storm Fund Assets	69		69		68
Available for sale debt securities amortized cost	1,462		$ 1,462		1,542
Special Use Funds Nuclear Decommissioning Funds Weighted Average Maturity			8 years
Fair Value Assumptions, Expected Term			1 year
FPL [Member] | Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Fair Value Disclosure	766		$ 766		693
Long Term Debt Including Current Maturities Fair Value Disclosure	13,420		13,420		11,783
FPL [Member] | Estimated Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Fair Value Disclosure	765		765		692
Long Term Debt Including Current Maturities Fair Value Disclosure	15,246		15,246		$ 12,613
Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
marketable securities, unrealized gain (loss) recognized during the period on securities still held	116	$ 78	481	$ 37
Equity Securities [Member] | FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
marketable securities, unrealized gain (loss) recognized during the period on securities still held	$ 77	$ 60	$ 311	$ 37