Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Deferred tax liabilities:
Property-related	$ 12,204	$ 11,700
Pension	455	489
Nuclear decommissioning trusts	219	258
Net unrealized gains on derivatives	528	390
Investments in partnerships and joint ventures	403	291
Other	1,196	769
Total deferred tax liabilities	15,005	13,897
Deferred tax assets and valuation allowance:
Decommissioning reserves	438	427
Postretirement benefits	141	154
Net operating loss carryforwards	604	1,070
Tax credit carryforwards	2,916	2,742
ARO and accrued asset removal costs	759	737
Other	836	820
Valuation allowance(a)	(223)	(323)
Net deferred tax assets	5,471	5,627
Net deferred income taxes	9,534	8,270
Deferred tax assets and liabilities included in the consolidated balance sheets [Abstract]
Deferred income taxes - current assets	0	739
Noncurrent other assets	293	264
Other current liabilities	0	(12)
Deferred income taxes - noncurrent liabilities	(9,827)	(9,261)
Net deferred income taxes	(9,534)	(8,270)
FPL [Member]
Deferred tax liabilities:
Property-related	8,040	7,457
Pension	480	459
Nuclear decommissioning trusts	0	0
Net unrealized gains on derivatives	0	0
Investments in partnerships and joint ventures	0	0
Other	695	435
Total deferred tax liabilities	9,215	8,351
Deferred tax assets and valuation allowance:
Decommissioning reserves	386	374
Postretirement benefits	95	99
Net operating loss carryforwards	4	0
Tax credit carryforwards	0	0
ARO and accrued asset removal costs	697	686
Other	303	318
Valuation allowance(a)	0	0
Net deferred tax assets	1,485	1,477
Net deferred income taxes	7,730	6,874
Deferred tax assets and liabilities included in the consolidated balance sheets [Abstract]
Deferred income taxes - current assets	0	0
Noncurrent other assets	0	0
Other current liabilities	0	(39)
Deferred income taxes - noncurrent liabilities	(7,730)	(6,835)
Net deferred income taxes	$ (7,730)	$ (6,874)