Income Taxes - Schedule of Significant Components of Deferred Income Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Assets
Other Employee Benefit Plans	$ 103	$ 105
Other	459	553
Total	562	658
Liabilities
Accelerated Depreciation	7,678	7,600
Other	630	627
Total	8,308	8,227
Net Deferred Income Tax Liabilities	$ 7,746	$ 7,569