Fair Value Measurements (Fair Value of Instruments Recorded at Carrying Amount) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special use funds: nuclear decommissioning fund assets	$ 5,756	$ 5,434
Available for sale debt securities amortized cost	1,875	1,820
Available For Sale Securities Equity Securities Amortized Cost	$ 1,591	1,543
Special Use Funds Nuclear Decommissioning Funds Weighted Average Maturity	8 years
Liabilities associated with assets held-for-sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt		373
Estimated Fair Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Fair Value Disclosure	$ 693	712
Other Investments Financial Instruments Primarily Notes Receivable Fair Value Disclosure	663	668
Long Term Debt Including Current Maturities Fair Value Disclosure	34,289	31,623
Estimated Fair Value [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long Term Debt Including Current Maturities Fair Value Disclosure	32,399	29,804
Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Fair Value Disclosure	693	712
Other Investments Financial Instruments Primarily Notes Receivable Fair Value Disclosure	508	526
Long Term Debt Including Current Maturities Fair Value Disclosure	32,149	30,418
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special use funds: nuclear decommissioning fund assets	3,861	3,665
Available for sale debt securities amortized cost	1,406	1,373
Available For Sale Securities Equity Securities Amortized Cost	$ 782	764
Special Use Funds Nuclear Decommissioning Funds Weighted Average Maturity	9 years
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	$ 539	557
Long Term Debt Including Current Maturities Fair Value Disclosure	11,984	11,211
FPL [Member] | Carrying Amount [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Special Use Funds Fair Value Disclosure	539	557
Long Term Debt Including Current Maturities Fair Value Disclosure	$ 10,549	$ 10,072