Fair Value Measurements (Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	$ 427	$ 508
Derivatives:
Derivative assets	2,470	2,386
Derivatives:
Derivative liability	2,052	1,340
Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	654	363
Special use funds:
Equity securities	3,824	3,963
U.S. Government and municipal bonds	694	717
Corporate debt securities	882	748
Mortgage-backed securities	421	517
Other debt securities	100	117
Other investments:
Equity Securities	45	46
Debt securities	207	151
Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(3,010)	(2,700)
Derivative assets	2,463	2,350
Derivatives:
Derivative liability, netting	(2,882)	(2,625)
Derivative liability	546	576
Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative asset, netting	(30)	(17)
Derivative assets	8	9
Derivatives:
Derivative liability, netting	(30)	(17)
Derivative liability	1,440	725
Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative asset, netting	(1)	1
Derivative assets	(1)	27
Derivatives:
Derivative liability, netting	(1)	1
Derivative liability	66	39
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	654	363
Special use funds:
Equity securities	1,799	1,875
U.S. Government and municipal bonds	525	567
Corporate debt securities	1	0
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	45	34
Debt securities	95	82
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	1,286	1,229
Derivatives:
Derivative Liability, Gross Liability	1,390	1,365
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	2,025	2,088
U.S. Government and municipal bonds	169	150
Corporate debt securities	881	748
Mortgage-backed securities	421	517
Other debt securities	100	117
Other investments:
Equity Securities	0	12
Debt securities	112	69
Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	2,429	2,082
Derivatives:
Derivative Liability, Gross Liability	1,606	1,446
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	38	24
Derivatives:
Derivative Liability, Gross Liability	1,449	598
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	0	26
Derivatives:
Derivative Liability, Gross Liability	67	38
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	0
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	1,758	1,739
Derivatives:
Derivative Liability, Gross Liability	432	390
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	2
Derivatives:
Derivative Liability, Gross Liability	21	144
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]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	103	60
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]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	97	64
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	101	118
Derivatives:
Derivative assets	2	3
Derivatives:
Derivative liability	11	13
FPL [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	123	156
Special use funds:
Equity securities	2,426	2,491
U.S. Government and municipal bonds	526	535
Corporate debt securities	626	533
Mortgage-backed securities	325	395
Other debt securities	92	111
FPL [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(2)	(1)
Derivative assets	2	3
Derivatives:
Derivative liability, netting	(2)	(1)
Derivative liability	11	13
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	123	156
Special use funds:
Equity securities	589	596
U.S. Government and municipal bonds	415	429
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	1,837	1,895
U.S. Government and municipal bonds	111	106
Corporate debt securities	626	533
Mortgage-backed securities	325	395
Other debt securities	92	111
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	2	3
Derivatives:
Derivative Liability, Gross Liability	5	5
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	0
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	2	1
Derivatives:
Derivative Liability, Gross Liability	8	9
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]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	56	54
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]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	$ 46	$ 64