Basis of Presentation - Performance Obligation, Expected Timing (Details)	Jun. 30, 2020 USD ($) MMcf Tcf
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Gross undelivered natural gas contracts (tcf) | Tcf	9.5
Net undelivered natural gas contracts (tcf) | Tcf	2.6
Price per barrel which trigger provision adjustments	$ 50
Increase in minimum volume commitments (MMcf/d) | MMcf	650
Increase in contractual minimum volumes (MMcf/d) | MMcf	450
Natural gas revenues	$ 7,691,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-07-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Natural gas revenues	$ 298,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing	6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Natural gas revenues	$ 553,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Natural gas revenues	$ 546,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Natural gas revenues	$ 550,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Natural gas revenues	$ 552,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Natural gas revenues	$ 5,192,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing