Non-Derivative Fair Value Measurements (Unrealized Gains (Losses) Recognized On Equity Securities Still Held at The Reporting Date) (Details) - Equity Securities [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gains (losses)	$ (25)	$ 223	$ 565	$ 65
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gains (losses)	$ (13)	$ 129	$ 375	$ 50