Derivatives and Risk Management (Summary of Before Tax Effect of Cash Flow Hedges on Consolidated Financial Statements) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	$ (945)	$ (139)
Settled Gain (Loss) on Derivatives Recognized in Earnings	(1,492)	362
Non-performance risk adjustment	1	1
Total gain (loss) on derivatives	(2,436)	224	$ 274
Purchased fixed price swaps | Natural Gas | Purchased
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(1)	2
Settled Gain (Loss) on Derivatives Recognized in Earnings	7	(3)
Purchased fixed price swaps | Oil | Purchased
Derivative Instruments, Gain (Loss) [Line Items]
Settled Gain (Loss) on Derivatives Recognized in Earnings	1	0
Purchased fixed price swaps | Natural gas storage | Purchased
Derivative Instruments, Gain (Loss) [Line Items]
Settled Gain (Loss) on Derivatives Recognized in Earnings	2	(1)
Fixed price swaps | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(237)	(25)
Settled Gain (Loss) on Derivatives Recognized in Earnings	(418)	142
Amortization of premium paid		9
Fixed price swaps | Oil
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(70)	0
Settled Gain (Loss) on Derivatives Recognized in Earnings	(86)	65
Fixed price swaps | Ethane
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	2	(21)
Settled Gain (Loss) on Derivatives Recognized in Earnings	(39)	6
Fixed price swaps | Propane
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(40)	(60)
Settled Gain (Loss) on Derivatives Recognized in Earnings	(173)	18
Fixed price swaps | Normal Butane
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(18)	(9)
Settled Gain (Loss) on Derivatives Recognized in Earnings	(53)	(2)
Fixed price swaps | Natural Gasoline
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(18)	(15)
Settled Gain (Loss) on Derivatives Recognized in Earnings	(59)	(1)
Fixed price swaps | Natural gas storage
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(1)	(1)
Settled Gain (Loss) on Derivatives Recognized in Earnings	(1)	2
Two-way costless collars | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(83)	10
Settled Gain (Loss) on Derivatives Recognized in Earnings	(325)	(5)
Two-way costless collars | Oil
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	1	(1)
Settled Gain (Loss) on Derivatives Recognized in Earnings	(4)	17
Two-way costless collars | Ethane
Derivative Instruments, Gain (Loss) [Line Items]
Settled Gain (Loss) on Derivatives Recognized in Earnings	(2)	0
Two-way costless collars | Propane
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	0	(1)
Settled Gain (Loss) on Derivatives Recognized in Earnings	0	2
Three-way costless collars | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(375)	(78)
Settled Gain (Loss) on Derivatives Recognized in Earnings	(335)	38
Three-way costless collars | Oil
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(41)	3
Settled Gain (Loss) on Derivatives Recognized in Earnings	(29)	9
Three-way costless collars | Propane
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(4)	0
Basis swaps | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	3	59
Settled Gain (Loss) on Derivatives Recognized in Earnings	92	76
Call options | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	(68)	(10)
Call options | Natural Gas | Purchased
Derivative Instruments, Gain (Loss) [Line Items]
Settled Gain (Loss) on Derivatives Recognized in Earnings	(66)	0
Call options | Oil
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	0	1
Call options | Oil | Purchased
Derivative Instruments, Gain (Loss) [Line Items]
Settled Gain (Loss) on Derivatives Recognized in Earnings	(2)	0
Put options | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	1	0
Settled Gain (Loss) on Derivatives Recognized in Earnings	(2)	0
Amortization of premium paid	2
Swaptions | Natural Gas
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	2	7
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Unsettled Gain (Loss) on Derivatives Recognized in Earnings	2	0
Settled Gain (Loss) on Derivatives Recognized in Earnings	$ 0	$ (1)