Variable Interest Entities (Consolidated Information of Variable Interest Entity) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 446	$ 452
Accounts receivable	1,042	931
Prepayments and other current assets	158	139
Plant, property, and equipment, net	22,540	22,352
Total Assets	28,740	28,753
Accounts payable	687	875
Asset retirement obligations	619	628
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Cash and cash equivalents	14	20
Accounts receivable	3	3
Prepayments and other current assets	2	1
Plant, property, and equipment, net	665	671
Total Assets	684	695
Accounts payable	8	15
Asset retirement obligations	20	20
Total liabilities	$ 28	$ 35