Derivatives and Risk Management (Schedule of Derivative Instruments Notional Amount, Weighted Average Contract Prices and Fair Value) (Details) bbl in Thousands, Mcf in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2021 USD ($) $ / bbl $ / MMBTU Mcf bbl
Financial protection on production - 2021 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	396
Fair value	$ (315)
Financial protection on production - 2021 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	2,983
Fair value	$ (59)
Financial protection on production - 2021 | Not Designated as Hedging Instrument | Ethane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	3,578
Fair value	$ (18)
Fixed Price Swaps - 2021 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	103
Weighted average price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.80
Fair value	$ (87)
Fixed Price Swaps - 2021 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	1,739
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	50.10
Fair value	$ (37)
Fixed Price Swaps - 2021 | Not Designated as Hedging Instrument | Ethane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	3,284
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	7.64
Fair value	$ (17)
Fixed Price Swaps - 2021 | Not Designated as Hedging Instrument | Propane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	4,261
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	24.00
Fair value	$ (84)
Fixed Price Swaps - 2021 | Not Designated as Hedging Instrument | Normal Butane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	1,245
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	29.04
Fair value	$ (27)
Fixed Price Swaps - 2021 | Not Designated as Hedging Instrument | Natural Gasoline
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	1,281
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	43.58
Fair value	$ (29)
Two-way Costless Collars-2021 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	140
Fair value	$ (101)
Two-way Costless Collars-2021 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	92
Fair value	$ (2)
Two-way Costless Collars-2021 | Not Designated as Hedging Instrument | Ethane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	294
Fair value	$ (1)
Two-way Costless Collars - 2021 Sold Calls | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.97
Two-way Costless Collars - 2021 Sold Calls | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	45.50
Two-way Costless Collars - 2021 Sold Calls | Not Designated as Hedging Instrument | Ethane
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	10.40
Three-way Costless-collars - 2021 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	153
Fair value	$ (127)
Three-way Costless-collars - 2021 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	1,152
Fair value	$ (20)
Three-Way Costless Collars - 2021 Sold Calls | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.86
Three-Way Costless Collars - 2021 Sold Calls | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	54.35
Financial protection on production - 2022 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	726
Fair value	$ (292)
Financial protection on production - 2022 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	4,583
Fair value	$ (54)
Financial protection on production - 2022 | Not Designated as Hedging Instrument | Ethane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	2,497
Fair value	$ (6)
Financial protection on production - 2022 | Not Designated as Hedging Instrument | Propane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	4,397
Fair value	$ (44)
Fixed Price Swaps - 2022 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	268
Weighted average price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.72
Fair value	$ (119)
Fixed Price Swaps - 2022 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	3,203
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	53.54
Fair value	$ (39)
Fixed Price Swaps - 2022 | Not Designated as Hedging Instrument | Ethane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	2,362
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	8.97
Fair value	$ (6)
Fixed Price Swaps - 2022 | Not Designated as Hedging Instrument | Propane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	4,092
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	25.90
Fair value	$ (42)
Fixed Price Swaps - 2022 | Not Designated as Hedging Instrument | Normal Butane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	1,295
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	29.16
Fair value	$ (16)
Fixed Price Swaps - 2022 | Not Designated as Hedging Instrument | Natural Gasoline
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	1,201
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	45.76
Fair value	$ (17)
Two Way Costless Collars - 2022 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	125
Fair value	$ (46)
Two Way Costless Collars - 2022 | Not Designated as Hedging Instrument | Ethane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	135
Fair value	$ 0
Two Way Costless Collars - 2022 Sold Calls | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.04
Two Way Costless Collars - 2022 Sold Calls | Not Designated as Hedging Instrument | Ethane
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	9.66
Three-Way Costless Collars - 2022 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	333
Fair value	$ (127)
Three-Way Costless Collars - 2022 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	1,380
Fair value	$ (15)
Three-Way Costless Collars - 2022 | Not Designated as Hedging Instrument | Propane
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	305
Fair value	$ (2)
Three-way Costless Collars 2022 - Sold Calls | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.94
Three-way Costless Collars 2022 - Sold Calls | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	57.05
Three-way Costless Collars 2022 - Sold Calls | Not Designated as Hedging Instrument | Propane
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	31.92
Financial protection on production- 2023 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	272
Fair value	$ (40)
Financial protection on production- 2023 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	2,114
Fair value	$ (16)
Fixed Price Swaps 2023 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	23
Weighted average price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.70
Fair value	$ (3)
Fixed Price Swaps 2023 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	846
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	55.98
Fair value	$ (4)
Two Way Costless Collars 2023 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	34
Fair value	$ (3)
Two Way Costless Collars Sold Calls 2023 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.72
Three Way Costless Collars - 2023 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	215
Fair value	$ (34)
Three Way Costless Collars - 2023 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	1,268
Fair value	$ (12)
Three Way Costless Collars - 2023 Sold Calls | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.00
Three Way Costless Collars - 2023 Sold Calls | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	56.12
Three Way Costless Collars 2024 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	11
Fair value	$ (1)
Three Way Costless Collars Sold Calls 2024 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.54
Fixed Price Swaps 2024 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	54
Weighted average price (in dollars per MMBtu, Bbl) | $ / bbl	53.15
Fair value	$ 0
Basis Swaps | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	639
Fair value	$ 112
Basis Swaps - 2021 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	166
Basis differential per MMBtu | $ / MMBTU	(0.47)
Fair value	$ 62
Basis Swaps - 2022 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	261
Basis differential per MMBtu | $ / MMBTU	(0.40)
Fair value	$ 40
Basis Swap - 2023 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	163
Basis differential per MMBtu | $ / MMBTU	(0.53)
Fair value	$ 7
Basis Swap - 2024 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	40
Basis differential per MMBtu | $ / MMBTU	(0.70)
Fair value	$ 2
Basis Swap - 2025 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	9
Basis differential per MMBtu | $ / MMBTU	(0.64)
Fair value	$ 1
Call options | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	170
Fair value	$ (73)
Call Options 2021 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	38
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.19
Fair value	$ (21)
Call Options 2021 | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Volume (Bcf, MBbls) | bbl	114
Cap price (in dollars per MMBtu, Bbl) | $ / bbl	60.00
Fair value	$ (1)
Call Options 2022 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	77
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.00
Fair value	$ (34)
Call Options 2023 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	46
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.94
Fair value	$ (14)
Call Options 2024 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	9
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.00
Fair value	$ (4)
Put options | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	14
Fair value	$ 0
Put Option 2021 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	9
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.00
Fair value	$ 0
Put Option 2022 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	5
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.00
Fair value	$ 0
Swaption 2021 | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	18
Cap price (in dollars per MMBtu, Bbl) | $ / MMBTU	3.00
Fair value	$ (5)
Storage 2021 | Not Designated as Hedging Instrument
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	3
Fair value	$ 0
Purchased Fixed Price Swaps, Storage, 2021 | Not Designated as Hedging Instrument
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	1
Weighted average price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.45
Basis differential per MMBtu | $ / MMBTU	0
Fair value	$ 1
Purchased Basis Swaps Storage, 2021 | Not Designated as Hedging Instrument
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	1
Weighted average price (in dollars per MMBtu, Bbl) | $ / MMBTU	0
Basis differential per MMBtu | $ / MMBTU	(0.88)
Fair value	$ 0
Fixed Price Swap, Storage, 2021 | Not Designated as Hedging Instrument
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	1
Weighted average price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.59
Basis differential per MMBtu | $ / MMBTU	0
Fair value	$ (1)
Basis Swaps Storage, 2021 | Not Designated as Hedging Instrument
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	0
Weighted average price (in dollars per MMBtu, Bbl) | $ / MMBTU	0
Basis differential per MMBtu | $ / MMBTU	(0.89)
Fair value	$ 0
Storage 2022 | Not Designated as Hedging Instrument
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	3
Fair value	$ (1)
Purchased Fixed Price Swaps, Storage, 2022 | Not Designated as Hedging Instrument
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	0
Weighted average price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.14
Basis differential per MMBtu | $ / MMBTU	0
Fair value	$ 0
Fixed Price Swap, Storage, 2022 | Not Designated as Hedging Instrument
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	2
Weighted average price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.82
Basis differential per MMBtu | $ / MMBTU	0
Fair value	$ (1)
Basis Swaps Storage, 2022 | Not Designated as Hedging Instrument
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	1
Weighted average price (in dollars per MMBtu, Bbl) | $ / MMBTU	0
Basis differential per MMBtu | $ / MMBTU	(0.57)
Fair value	$ 0
Purchased Fixed Price Swaps, Marketing, 2021 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Volume (Bcf, MBbls) | Mcf	2
Weighted average price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.44
Fair value	$ 3
Sold Puts | Three-Way Costless Collars - 2021 Sold Puts | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.18
Sold Puts | Three-Way Costless Collars - 2021 Sold Puts | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	39.22
Sold Puts | Three-Way Costless Collars - 2022 Sold Puts | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.06
Sold Puts | Three-Way Costless Collars - 2022 Sold Puts | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	39.89
Sold Puts | Three-Way Costless Collars - 2022 Sold Puts | Not Designated as Hedging Instrument | Propane
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	16.80
Sold Puts | Three Way Costless Collars - 2023 Sold Puts | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.09
Sold Puts | Three Way Costless Collars - 2023 Sold Puts | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	33.97
Sold Puts | Three Way Costless Collars Sold Puts 2024 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.25
Purchased Puts | Two-way Costless Collars - 2021 Purchased Puts | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.62
Purchased Puts | Two-way Costless Collars - 2021 Purchased Puts | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	37.50
Purchased Puts | Two-way Costless Collars - 2021 Purchased Puts | Not Designated as Hedging Instrument | Ethane
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	7.14
Purchased Puts | Three-Way Costless Collars - 2021 Purchased Puts | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.51
Purchased Puts | Three-Way Costless Collars - 2021 Purchased Puts | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	49.05
Purchased Puts | Two Way Costless Collars - 2022 Purchased Puts | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.65
Purchased Puts | Two Way Costless Collars - 2022 Purchased Puts | Not Designated as Hedging Instrument | Ethane
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	7.56
Purchased Puts | Three Way Costless Collars 2022 - Purchased Puts | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.51
Purchased Puts | Three Way Costless Collars 2022 - Purchased Puts | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	50.23
Purchased Puts | Three Way Costless Collars 2022 - Purchased Puts | Not Designated as Hedging Instrument | Propane
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	21.00
Purchased Puts | Two Way Costless Collars Purchased Puts 2023 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.50
Purchased Puts | Three Way Costless Collars - 2023 Purchased Puts | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.54
Purchased Puts | Three Way Costless Collars - 2023 Purchased Puts | Not Designated as Hedging Instrument | Oil
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / bbl	45.51
Purchased Puts | Three Way Costless Collars Purchased Puts 2024 | Not Designated as Hedging Instrument | Natural Gas
Derivative [Line Items]
Floor price (in dollars per MMBtu, Bbl) | $ / MMBTU	2.80