Employee Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	$ 21	$ 20
Interest cost	23	29
Expected return on plan assets	(80)	(79)
Amortization of prior service benefit	0	0
Amortization of actuarial loss	4	0
Special termination benefits	2	0
Net periodic benefit (income) cost	(30)	(30)
Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	0	0
Interest cost	2	3
Expected return on plan assets	0	0
Amortization of prior service benefit	(4)	(4)
Amortization of actuarial loss	1	0
Special termination benefits	0	0
Net periodic benefit (income) cost	(1)	(1)
FPL [Member] | Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	(19)	(18)
FPL [Member] | Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	$ (1)	$ (1)