Supplemental Oil and Gas Disclosures (Unaudited) (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) Mcfe	Dec. 31, 2020 USD ($) Mcfe location	Dec. 31, 2019 USD ($) Mcfe location	Dec. 31, 2018 Mcfe
Natural Gas and Oil Properties [Line Items]
Net unevaluated costs excluded from amortization, cumulative	$ 2,231	$ 1,472
Capitalized interest	220
Capitalized interest based on weighted average cost of borrowings	97	88	$ 109
Capitalized internal costs related to acquisition, exploration and development	$ 64	$ 56	$ 77
Percentage of present worth of proved reserves evaluated in audit	99.00%	97.00%	99.00%
Proved reserves, end of period, (bcfe) | Mcfe	21,148,000,000	11,990,000,000	12,721,000,000	11,921,000,000
Proved undeveloped reverses (energy) | Mcfe	0	2,437,000,000	929,000,000
Number of locations | location		138	90
Present value of proved reserves, discounted basis		$ 207	$ 50
Montage Resources Corporation
Natural Gas and Oil Properties [Line Items]
Net unevaluated costs excluded from amortization, cumulative	$ 117
Undeveloped Properties Southwest Appalachia
Natural Gas and Oil Properties [Line Items]
Net unevaluated costs excluded from amortization, cumulative	1,100
Undeveloped Properties Northeast Appalachia
Natural Gas and Oil Properties [Line Items]
Net unevaluated costs excluded from amortization, cumulative	759
Wells In Progress
Natural Gas and Oil Properties [Line Items]
Net unevaluated costs excluded from amortization, cumulative	51
Capitalized interest	$ 220
United States
Natural Gas and Oil Properties [Line Items]
Proved reserves, end of period, (bcfe) | Mcfe	21,148,000,000	11,990,000,000	12,721,000,000	11,921,000,000
Proved undeveloped reverses (energy) | Mcfe	9,813,000,000	3,787,000,000	6,300,000,000