Derivative Instruments (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Derivative [Line Items]
Reclassification from AOCI, before Tax		$ 23
Reclassification from AOCI, Net of Tax		$ 3
Total loss to be reclassified during next 12 months	$ 7
Margin cash collateral received from counterparties that was not offset against derivative assets	8		$ 6
Margin cash collateral provided to counterparties that was not offset against derivative assets or liabilities	384		315
FPL
Derivative [Line Items]
Margin cash collateral received from counterparties that was not offset against derivative assets	0		0
Margin cash collateral provided to counterparties that was not offset against derivative assets or liabilities	$ 0		$ 0