Long-Term Debt And Lease Obligation (Book Value And Principal Amounts Of Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument
Book value	$ 789	$ 789
Principal amount	$ 793	$ 793
6.900% Senior Debentures, Due 2028
Debt Instrument
Interest rate	6.90%	6.90%
Book value	$ 27	$ 27
Principal amount	$ 28	$ 28
6.920% Senior Debentures, Due 2028
Debt Instrument
Interest rate	6.92%	6.92%
Book value	$ 391	$ 391
Principal amount	$ 391	$ 391
6.125% Senior Notes, Due 2034
Debt Instrument
Interest rate	6.125%	6.125%
Book value	$ 371	$ 371
Principal amount	$ 374	$ 374