Variable Interest Entities (Consolidated Information of Variable Interest Entity) (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Cash and cash equivalents	$ 77	$ 452
Restricted cash and cash equivalents	19	24
Accounts receivable	991	931
Prepayments and other current assets	167	139
Plant, property, and equipment, net	21,627	22,352
Total assets	29,040	28,753
Accounts payable	906	875
Other current liabilities	181	156
Asset retirement obligations	620	628
Other non‑current liabilities	382	375
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
Cash and cash equivalents	24	21
Restricted cash and cash equivalents	0	1
Accounts receivable	10	3
Prepayments and other current assets	3	2
Plant, property, and equipment, net	841	856
Total assets	878	883
Accounts payable	18	17
Other current liabilities	0	2
Asset retirement obligations	23	23
Other non‑current liabilities		4
Total liabilities	$ 41	$ 46