Commitments and Contingencies (Schedule of Future Obligation under Transportation Agreements) (Details) $ in Millions	Dec. 31, 2019 USD ($)
Other Commitments [Line Items]
Total	$ 8,470
Less than 1 year	768
1 to 3 years	1,235
3 to 5 years	1,169
5 to 8 years	1,739
Obligation under transportation, more than 8 years	3,559
Infrastructure Currently in Service
Other Commitments [Line Items]
Total	7,414
Less than 1 year	767
1 to 3 years	1,200
3 to 5 years	1,066
5 to 8 years	1,531
Obligation under transportation, more than 8 years	2,850
Pending Regulatory Approval and/or Construction
Other Commitments [Line Items]
Total	1,056
Less than 1 year	1
1 to 3 years	35
3 to 5 years	103
5 to 8 years	208
Obligation under transportation, more than 8 years	$ 709