Revenue Recognition (Details) - USD ($) $ in Millions		3 Months Ended
	Jan. 01, 2018	Mar. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contracts with customers		$ 3,300
FPL [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contracts with customers		2,600
NextEra Energy Resources [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue, remaining performance obligation		$ 750
Sales Revenue, Net [Member] | FPL [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Concentration risk, percentage		90.00%
Customer Contracts [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable balances related to contracts with customers		$ 1,300
Customer Contracts [Member] | FPL [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Accounts receivable balances related to contracts with customers		$ 951
Retained Earnings [Member] | Accounting Standards Update 2014-09 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net reduction to retained earnings	$ 25