Income Taxes - Deferred Tax Assets and Valuation Allowances (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets and valuation allowances:
Net operating loss, deferred tax assets	$ 2,024	$ 2,007
Tax credits, deferred tax assets	300	$ 303
General Business Credits \| Expires from 2036 - 2042
Deferred tax assets and valuation allowances:
Tax credits, unused amount	300
Tax credits, deferred tax assets	300
Tax credits, valuation allowance	0
U.S. Federal \| Indefinite Tax Period
Deferred tax assets and valuation allowances:
Net operating loss, unused amount	6,565
Net operating loss, deferred tax assets	1,379
Net operating loss, valuation allowance	0
U.S. Federal \| Expires from 2035 - 2037
Deferred tax assets and valuation allowances:
Net operating loss, unused amount	1,716
Net operating loss, deferred tax assets	360
Net operating loss, valuation allowance	0
State \| Expires from 2024 - 2043
Deferred tax assets and valuation allowances:
Net operating loss, unused amount	5,293
Net operating loss, deferred tax assets	254
Net operating loss, valuation allowance	(46)
Foreign \| Indefinite Tax Period
Deferred tax assets and valuation allowances:
Net operating loss, unused amount	90
Net operating loss, deferred tax assets	31
Net operating loss, valuation allowance	$ (31)

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount, before allocation of a valuation allowances, of deferred tax assets attributable to deductible tax credit carryforwards including, but not limited to, research, foreign, general business, alternative minimum tax, and other deductible tax credit carryforwards.

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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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The portion of the valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from net operating loss carryforwards for which it is more likely than not that a tax benefit will not be realized.

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The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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Amount of valuation allowance pertaining to the deferred tax asset representing potential future taxable deductions from tax credit carryforwards for which it is more likely than not that a tax benefit will not be realized.

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