Income Taxes - Components of Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Federal:
Current	$ 105	$ 167	$ 30
Deferred	(148)	115	1,153
Total federal	(43)	282	1,183
State:
Current	18	23	63
Deferred	69	143	330
Total state	87	166	393
Total income taxes	44	448	1,576
FPL[Member]
Federal:
Current	53	348	251
Deferred	388	(29)	134
Total federal	441	319	385
State:
Current	44	49	91
Deferred	125	73	63
Total state	169	122	154
Total income taxes	$ 610	$ 441	$ 539