Employee Retirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	$ 23	$ 22	$ 68	$ 64
Interest cost	16	23	48	69
Expected return on plan assets	(85)	(80)	(255)	(241)
Amortization of prior service benefit	0	(1)	(1)	(1)
Amortization of actuarial loss	6	4	18	13
Special termination benefits	0	4	0	13
Net periodic benefit (income) cost	(40)	(28)	(122)	(83)
Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Service cost	1	0	1	1
Interest cost	1	3	3	6
Expected return on plan assets	0	0	0	0
Amortization of prior service benefit	(4)	(4)	(11)	(12)
Amortization of actuarial loss	1	0	4	2
Special termination benefits	0	0	0	0
Net periodic benefit (income) cost	(1)	(1)	(3)	(3)
FPL [Member] | Pension Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	(27)	(21)	(81)	(63)
FPL [Member] | Postretirement Benefits [Member]
Net periodic benefit (income) cost [Abstract]
Net periodic benefit (income) cost	$ (1)	$ (1)	$ (3)	$ (3)