Income Taxes (Components of Deferred Tax Balances) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Deferred tax liabilities:
Differences between book and tax basis of property	$ 379	$ 0
Right of use lease asset	41	45
Accrued pension costs	1	0
Other	3	3
Total deferred tax liabilities	424	48
Deferred tax assets:
Accrued compensation	50	44
Accrued pension costs	0	6
Asset retirement obligations	24	25
Net operating loss carryforward	469	585
Future lease payments	41	46
Derivative activity	340	362
Capital loss carryover	27	28
Interest carryover	41	11
Other	21	20
Total deferred tax assets	1,013	1,127
Valuation allowance	(589)	(1,079)	$ (1,539)
Net deferred tax asset	$ 0	$ 0