Income Taxes - Income Tax Provision (Benefit) Differed from Amounts Computed at the Statutory Federal Income Tax Rate and Significant Components (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Tax Disclosure [Abstract]
Income tax provision (benefit) at statutory rate	$ 711	$ 208	$ (537)
State income tax provision (benefit), net of federal income tax benefit	46	13	(34)
Nondeductible employee meals	15	12	7
Nondeductible transportation fringe benefit	13	10	8
Valuation allowance	(21)	(10)	(38)
Other, net	5	20	1
Income tax expense (benefit)	769	253	(593)
Current	13	5	(10)
Deferred	$ 756	$ 248	$ (583)