Derivative Instruments (Balance Sheet Disclosure) (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Derivative assets	$ 2,114	$ 2,217
Derivative Asset, Current	496	570
Derivative Asset, Noncurrent	1,618	1,647
Derivative liability	1,032	1,510
Derivative Liability, Current	437	311
Derivative Liability, Noncurrent	595	1,199
Non Current Derivative Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Amount Offset Against Collateral	66	184
Current derivative liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Collateral, Right to Reclaim Cash, Offset	45	136
Commodity Contract [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	1,970	2,154
Derivative liability	663	500
Derivative asset, netting	(2,197)	(2,325)
Derivative liability, netting	(2,176)	(2,277)
Commodity Contract [Member] \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	775	919
Derivative Liability, Gross Liability	858	1,004
Commodity Contract [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	1,893	1,881
Derivative Liability, Gross Liability	1,639	1,468
Commodity Contract [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	1,499	1,679
Derivative Liability, Gross Liability	342	305
Interest Rate Contract [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	149	40
Derivative liability	349	1,001
Derivative asset, netting	(69)	(41)
Derivative liability, netting	(69)	(41)
Interest Rate Contract [Member] \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	0	0
Derivative Liability, Gross Liability	0	0
Interest Rate Contract [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	218	81
Derivative Liability, Gross Liability	418	1,042
Interest Rate Contract [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	0	0
Derivative Liability, Gross Liability	0	0
Currency Swap [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	(5)	23
Derivative liability	20	9
Derivative asset, netting	(40)	(34)
Derivative liability, netting	(40)	(34)
Currency Swap [Member] \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	0	0
Derivative Liability, Gross Liability	0	0
Currency Swap [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	35	57
Derivative Liability, Gross Liability	60	43
Currency Swap [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	0	0
Derivative Liability, Gross Liability	0	0
FPL [Member]
Derivatives, Fair Value [Line Items]
Derivative liability		3
FPL [Member] \| Other Current Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Current	8	2
FPL [Member] \| Other Noncurrent Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Noncurrent		1
FPL [Member] \| Other Current Assets [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Current	2	3
FPL [Member] \| Commodity Contract [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative assets	2	3
Derivative liability	8	3
Derivative asset, netting	(1)	0
Derivative liability, netting	(1)	0
FPL [Member] \| Commodity Contract [Member] \| Quoted Prices in Active Markets for Identical Assets or Liabilities (Level 1) [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	0	0
Derivative Liability, Gross Liability	0	0
FPL [Member] \| Commodity Contract [Member] \| Fair Value, Inputs, Level 2 [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	1	1
Derivative Liability, Gross Liability	5	0
FPL [Member] \| Commodity Contract [Member] \| Fair Value, Inputs, Level 3 [Member] \| Fair value measurements made on a recurring basis [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Gross Asset	2	2
Derivative Liability, Gross Liability	$ 4	$ 3

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and elected not to be offset.

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Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, and obligation to return cash collateral under master netting arrangements.

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