Non-Derivative Fair Value Measurements (Fair Value of Instruments Recorded at Other than Fair Value) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Fair Value Disclosure	$ 919	$ 892
Other Investments Financial Instruments Fair Value Disclosure	29	30
Long Term Debt Including Current Maturities Fair Value Disclosure	46,082	39,667
Reported Value Measurement [Member] \| Other Current Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long Term Debt Including Current Maturities Fair Value Disclosure	463
Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Fair Value Disclosure	920	891
Other Investments Financial Instruments Fair Value Disclosure	29	30
Long Term Debt Including Current Maturities Fair Value Disclosure	51,525	42,928
FPL[Member] \| Reported Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Fair Value Disclosure	718	706
Long Term Debt Including Current Maturities Fair Value Disclosure	15,676	14,161
FPL[Member] \| Estimate of Fair Value Measurement [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Fair Value Disclosure	719	705
Long Term Debt Including Current Maturities Fair Value Disclosure	$ 19,470	$ 16,448