Variable Interest Entities (Consolidated Information of Variable Interest Entity) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 452	$ 32
Accounts receivable	931	853
Prepayments and other current assets	120	104
Plant, property, and equipment, net	22,352	21,017
Total Assets	28,753	29,666	$ 26,837
Accounts payable	875	661
Asset retirement obligations	628	553
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Cash and cash equivalents	20	7
Accounts receivable	3	5
Prepayments and other current assets	1	1
Plant, property, and equipment, net	671	692
Total Assets	695	705
Accounts payable	15	3
Asset retirement obligations	20	19
Total liabilities	$ 35	$ 22