Non-Derivative Fair Value Measurements (Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	$ 549	$ 441
Derivatives:
Derivative assets	2,143	2,217
Derivatives:
Derivative liability	2,388	1,510
NEER Segment
Derivatives:
Contingent consideration liabilities	264
Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	313	742
Special use funds:
Equity securities	5,307	4,726
U.S. Government and municipal bonds	820	717
Corporate debt securities	869	871
Mortgage-backed securities	455	422
Other debt securities	149	124
Other investments:
Equity Securities	60	62
Debt securities	239	218
Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(4,433)	(2,325)
Derivative assets	2,062	2,154
Derivatives:
Derivative liability, netting	(4,403)	(2,277)
Derivative liability	1,666	500
Fair value measurements made on a recurring basis [Member] | Interest Rate Contract [Member]
Derivatives:
Derivative asset, netting	(39)	(41)
Derivative assets	85	40
Derivatives:
Derivative liability, netting	(39)	(41)
Derivative liability	685	1,001
Fair value measurements made on a recurring basis [Member] | Foreign Currency Swap [Member]
Derivatives:
Derivative asset, netting	(30)	(34)
Derivative assets	(4)	23
Derivatives:
Derivative liability, netting	(30)	(34)
Derivative liability	37	9
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	313	742
Special use funds:
Equity securities	2,451	2,237
U.S. Government and municipal bonds	756	590
Corporate debt securities	1	1
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	60	62
Debt securities	101	91
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	1,468	919
Derivatives:
Derivative Liability, Gross Liability	1,721	1,004
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	2,856	2,489
U.S. Government and municipal bonds	64	127
Corporate debt securities	868	870
Mortgage-backed securities	455	422
Other debt securities	149	124
Other investments:
Equity Securities	0	0
Debt securities	122	127
Significant Other Observable Inputs (Level 2) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	3,507	1,881
Derivatives:
Derivative Liability, Gross Liability	3,412	1,468
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	124	81
Derivatives:
Derivative Liability, Gross Liability	724	1,042
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	26	57
Derivatives:
Derivative Liability, Gross Liability	67	43
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	16	0
Significant Unobservable Inputs (Level 3) [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative Asset, Gross Asset	1,520	1,679
Derivatives:
Derivative Liability, Gross Liability	936	305
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	0	0
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	75	111
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	5	42
FPL [Member]
Fair Value, Assets and Liabilities Measured on Recurring [Line Items]
Restricted cash	79	135
Derivatives:
Derivative liability		3
FPL [Member] | Fair value measurements made on a recurring basis [Member]
Cash equivalents:
Equity securities	85	137
Special use funds:
Equity securities	3,409	3,012
U.S. Government and municipal bonds	661	536
Corporate debt securities	648	627
Mortgage-backed securities	330	335
Other debt securities	135	119
Other investments:
Equity Securities	12	12
FPL [Member] | Fair value measurements made on a recurring basis [Member] | Commodity Contract [Member]
Derivatives:
Derivative asset, netting	(2)	0
Derivative assets	9	3
Derivatives:
Derivative liability, netting	(2)	0
Derivative liability	3	3
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	85	137
Special use funds:
Equity securities	819	752
U.S. Government and municipal bonds	613	449
Corporate debt securities	0	0
Mortgage-backed securities	0	0
Other debt securities	0	0
Other investments:
Equity Securities	12	12
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	2,590	2,260
U.S. Government and municipal bonds	48	87
Corporate debt securities	648	627
Mortgage-backed securities	330	335
Other debt securities	135	119
Other investments:
Equity Securities	0	0
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	6	1
Derivatives:
Derivative Liability, Gross Liability	0	0
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
Other investments:
Equity 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	5	2
Derivatives:
Derivative Liability, Gross Liability	5	3
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	73	91
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	$ 5	$ 42