Employee Retirement Benefits - Net Periodic Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	$ 64	$ 86	$ 90
Interest cost	132	77	64
Expected return on plan assets	(392)	(363)	(339)
Amortization of actuarial loss	0	0	24
Amortization of prior service benefit	0	(1)	(1)
Special termination benefits	0	52	0
Benefit plan settlement	0	27	0
Net periodic (income) cost	(196)	(122)	(162)
Other Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	1	1	2
Interest cost	9	5	4
Expected return on plan assets	0	0	0
Amortization of actuarial loss	0	3	5
Amortization of prior service benefit	0	(4)	(15)
Special termination benefits	0	0	0
Benefit plan settlement	0	0	0
Net periodic (income) cost	10	5	(4)
FPL [Member] | Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic (income) cost	(127)	(76)	(108)
FPL [Member] | Other Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic (income) cost	$ 8	$ 4	$ (4)