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
	Mar. 31, 2021	Mar. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gains (losses)	$ 247	$ (808)
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Unrealized gains (losses)	$ 161	$ (502)