Summarized Financial Information of NEECH - Balance Sheets (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
PROPERTY, PLANT AND EQUIPMENT
Electric plant in service and other property	$ 93,783	$ 87,013	$ 80,330
Accumulated depreciation and amortization	21,367	20,101	18,944
Total property, plant and equipment - net	72,416	66,912
CURRENT ASSETS
Cash and cash equivalents	1,714	1,292
Receivables	2,737	2,439
Other	2,706	3,678
Total current assets	7,157	7,409
OTHER ASSETS
Investment in subsidiaries	0	0
Other	18,254	15,672
Total other assets	18,254	15,672
TOTAL ASSETS	97,827	89,993	$ 82,479
CAPITALIZATION
Common shareholders' equity	28,208	24,341
Noncontrolling interests	1,290	990
Long-term debt	31,463	27,818
Total capitalization	60,961	53,149
CURRENT LIABILITIES
Debt due within one year	3,618	3,022
Accounts payable	3,235	3,447
Other	4,379	4,450
Total current liabilities	11,232	10,919
OTHER LIABILITIES AND DEFERRED CREDITS
Asset retirement obligations	3,031	2,736
Deferred income taxes	5,754	11,101
Other	16,849	12,088
Total other liabilities and deferred credits	25,634	25,925
COMMITMENTS AND CONTINGENCIES
TOTAL CAPITALIZATION AND LIABILITIES	97,827	89,993
Reportable Legal Entities [Member] | NEE (Guarantor) [Member]
PROPERTY, PLANT AND EQUIPMENT
Electric plant in service and other property	20	28
Accumulated depreciation and amortization	15	18
Total property, plant and equipment - net	5	10
CURRENT ASSETS
Cash and cash equivalents	1	1
Receivables	442	88
Other	5	2
Total current assets	448	91
OTHER ASSETS
Investment in subsidiaries	27,825	24,323
Other	591	867
Total other assets	28,416	25,190
TOTAL ASSETS	28,869	25,291
CAPITALIZATION
Common shareholders' equity	28,208	24,341
Noncontrolling interests	0	0
Long-term debt	0	0
Total capitalization	28,208	24,341
CURRENT LIABILITIES
Debt due within one year	0	0
Accounts payable	3	1
Other	325	231
Total current liabilities	328	232
OTHER LIABILITIES AND DEFERRED CREDITS
Asset retirement obligations	0	0
Deferred income taxes	(82)	82
Other	415	636
Total other liabilities and deferred credits	333	718
COMMITMENTS AND CONTINGENCIES
TOTAL CAPITALIZATION AND LIABILITIES	28,869	25,291
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
PROPERTY, PLANT AND EQUIPMENT
Electric plant in service and other property	41,782	38,671
Accumulated depreciation and amortization	8,551	7,778
Total property, plant and equipment - net	33,231	30,893
CURRENT ASSETS
Cash and cash equivalents	1,679	1,258
Receivables	1,633	1,615
Other	1,283	1,877
Total current assets	4,595	4,750
OTHER ASSETS
Investment in subsidiaries	0	0
Other	9,941	8,992
Total other assets	9,941	8,992
TOTAL ASSETS	47,767	44,635
CAPITALIZATION
Common shareholders' equity	10,745	7,699
Noncontrolling interests	1,290	990
Long-term debt	20,227	18,112
Total capitalization	32,262	26,801
CURRENT LIABILITIES
Debt due within one year	1,215	2,237
Accounts payable	2,427	2,668
Other	2,073	2,624
Total current liabilities	5,715	7,529
OTHER LIABILITIES AND DEFERRED CREDITS
Asset retirement obligations	984	816
Deferred income taxes	1,247	3,002
Other	7,559	6,487
Total other liabilities and deferred credits	9,790	10,305
COMMITMENTS AND CONTINGENCIES
TOTAL CAPITALIZATION AND LIABILITIES	47,767	44,635
Consolidation, Eliminations [Member]
PROPERTY, PLANT AND EQUIPMENT
Electric plant in service and other property	51,981	48,314
Accumulated depreciation and amortization	12,801	12,305
Total property, plant and equipment - net	39,180	36,009
CURRENT ASSETS
Cash and cash equivalents	34	33
Receivables	662	736
Other	1,418	1,799
Total current assets	2,114	2,568
OTHER ASSETS
Investment in subsidiaries	(27,825)	(24,323)
Other	7,722	5,813
Total other assets	(20,103)	(18,510)
TOTAL ASSETS	21,191	20,067
CAPITALIZATION
Common shareholders' equity	(10,745)	(7,699)
Noncontrolling interests	0	0
Long-term debt	11,236	9,706
Total capitalization	491	2,007
CURRENT LIABILITIES
Debt due within one year	2,403	785
Accounts payable	805	778
Other	1,981	1,595
Total current liabilities	5,189	3,158
OTHER LIABILITIES AND DEFERRED CREDITS
Asset retirement obligations	2,047	1,920
Deferred income taxes	4,589	8,017
Other	8,875	4,965
Total other liabilities and deferred credits	15,511	14,902
COMMITMENTS AND CONTINGENCIES
TOTAL CAPITALIZATION AND LIABILITIES	$ 21,191	$ 20,067