Income Taxes - Components of Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017		Dec. 31, 2016
Federal:
Current	$ 30	$ 100		$ 72
Deferred	1,153	(1,047)		1,071
Total federal	1,183	(947)		1,143
State:
Current	63	88		76
Deferred	330	199		160
Total state	393	287		236
Total income tax expense (benefit)	1,576	(660)	[1]	1,379	[1]
FPL[Member]
Federal:
Current	251	168		72
Deferred	134	776		830
Total federal	385	944		902
State:
Current	91	29		57
Deferred	63	133		92
Total state	154	162		149
Total income tax expense (benefit)	$ 539	$ 1,106	[2]	$ 1,051	[2]

[1] Amounts have been retrospectively adjusted as discussed in Note 14 and Note 3 - Amendments to Presentation of Retirement Benefits.

[2] Amounts have been retrospectively adjusted as discussed in Note 14.