Fair Value Measurements (Fair Value of Instruments Recorded at Other Than Fair Value and Special Use Funds) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Nuclear Decommissioning Funds Weighted Average Maturity	8 years
Special use funds: nuclear decommissioning fund assets	$ 6,291		$ 5,818
Special Use Funds Storm Fund Assets	69		68
Available for sale debt securities amortized cost	$ 1,980		1,994
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	$ 930		884
Other Investments Financial Instruments Primarily Notes Receivable Fair Value Disclosure	39		54
Long Term Debt Including Current Maturities Fair Value Disclosure	32,497		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	929		883
Other Investments Financial Instruments Primarily Notes Receivable Fair Value Disclosure	39		54
Long Term Debt Including Current Maturities Fair Value Disclosure	$ 34,165		30,043
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Nuclear Decommissioning Funds Weighted Average Maturity	8 years
Special use funds: nuclear decommissioning fund assets	$ 4,298		3,987
Special Use Funds Storm Fund Assets	69		68
Available for sale debt securities amortized cost	$ 1,485		1,542
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	$ 759		693
Long Term Debt Including Current Maturities Fair Value Disclosure	12,379		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	758		692
Long Term Debt Including Current Maturities Fair Value Disclosure	13,756		$ 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	367	$ (20)
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	234
Liabilities Associated with Assets Held-for-Sale [Member] | Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long Term Debt Including Current Maturities Fair Value Disclosure	$ 876