Fair Value Measurements (Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Special Use Funds Storm Fund Assets	$ 69	$ 68
Derivatives:
Derivative assets	2,431	1,919
Derivatives:
Derivative liability	1,235	1,191
Restricted cash	684	4,615
Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	861	486
Special use funds:
Equity securities	3,569	3,046
U.S. Government and municipal bonds	674	604
Corporate debt securities	747	728
Mortgage-backed securities	444	478
Other debt securities	157	146
Other investments:
Equity Securities	30	24
Debt securities	174	126
Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(2,753)	(2,811)
Derivative assets	2,399	1,840
Derivatives:
Derivative liability, netting	(2,965)	(2,622)
Derivative liability	629	683
Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative asset, netting	(5)	(7)
Derivative assets	9	49
Derivatives:
Derivative liability, netting	(5)	(7)
Derivative liability	569	465
Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative asset, netting	0	13
Derivative assets	23	30
Derivatives:
Derivative liability, netting	0	13
Derivative liability	37	43
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	861	486
Special use funds:
Equity securities	1,679	1,445
U.S. Government and municipal bonds	561	449
Corporate debt securities	0	0
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	18	13
Debt securities	106	36
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	1,296	1,379
Derivatives:
Derivative Liability, Gross Liability	1,493	1,329
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	0	0
Derivatives:
Derivative Liability, Gross Liability	0	0
Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative Asset, Gross Asset	0	0
Derivatives:
Derivative Liability, Gross Liability	0	0
Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	0	0
Special use funds:
Equity securities	1,890	1,601
U.S. Government and municipal bonds	113	155
Corporate debt securities	747	728
Mortgage-backed securities	444	478
Other debt securities	157	145
Other investments:
Equity Securities	12	11
Debt securities	68	90
Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	2,088	1,923
Derivatives:
Derivative Liability, Gross Liability	1,709	1,410
Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	14	56
Derivatives:
Derivative Liability, Gross Liability	429	336
Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative Asset, Gross Asset	23	17
Derivatives:
Derivative Liability, Gross Liability	37	30
Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	0	0
Special use funds:
Equity securities	0	0
U.S. Government and municipal bonds	0	0
Corporate debt securities	0	0
Mortgage-backed securities	0	0
Other debt securities	0	1
Other investments:
Equity Securities	0	0
Debt securities	0	0
Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	1,768	1,349
Derivatives:
Derivative Liability, Gross Liability	392	566
Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	0	0
Derivatives:
Derivative Liability, Gross Liability	145	136
Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative Asset, Gross Asset	0	0
Derivatives:
Derivative Liability, Gross Liability	0	0
Other Current Assets [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Derivatives:
Restricted cash	92	85
Other Noncurrent Assets [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Derivatives:
Restricted cash	90
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Special Use Funds Storm Fund Assets	69	68
Derivatives:
Derivative assets	6	0
Derivatives:
Derivative liability	17	41
Restricted cash	167	142
FPL [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	209	206
Special use funds:
Equity securities	2,235	1,850
U.S. Government and municipal bonds	505	470
Corporate debt securities	534	544
Mortgage-backed securities	334	367
Other debt securities	133	132
FPL [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(2)	(2)
Derivative assets	6	0
Derivatives:
Derivative liability, netting	(2)	(2)
Derivative liability	17	41
FPL [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	209	206
Special use funds:
Equity securities	520	398
U.S. Government and municipal bonds	417	350
Corporate debt securities	0	0
Mortgage-backed securities	0	0
Other debt securities	0	0
FPL [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	0	0
Derivatives:
Derivative Liability, Gross Liability	0	0
FPL [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	0	0
Special use funds:
Equity securities	1,715	1,452
U.S. Government and municipal bonds	88	120
Corporate debt securities	534	544
Mortgage-backed securities	334	367
Other debt securities	133	131
FPL [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	7	2
Derivatives:
Derivative Liability, Gross Liability	5	7
FPL [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	0	0
Special use funds:
Equity securities	0	0
U.S. Government and municipal bonds	0	0
Corporate debt securities	0	0
Mortgage-backed securities	0	0
Other debt securities	0	1
FPL [Member] | Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	1	0
Derivatives:
Derivative Liability, Gross Liability	14	36
FPL [Member] | Other Current Assets [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Derivatives:
Restricted cash	77	$ 81
FPL [Member] | Other Noncurrent Assets [Member] | Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] | Fair value measurements made on a recurring basis [Member]
Derivatives:
Restricted cash	$ 90