Amount of asset segregated and restricted to provide benefit under defined benefit plan. Asset includes, but is not limited to, stock, bond, other investment, earning from investment, and contribution by employer and employee.

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Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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Benefit Plans - Schedule of Weighted Average Target Asset Allocation and Actual Percentage of Plan Assets by Asset Category (Details) - Pension benefits - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Actual percentage of plan assets	100.00%	100.00%
Fair value of plan assets	$ 4,440	$ 4,430	$ 6,525
Equity securities
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Actual percentage of plan assets	26.00%	27.00%
Equity securities \| Minimum
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	17.00%
Equity securities \| Maximum
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	36.00%
Fixed income securities
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Actual percentage of plan assets	48.00%	49.00%
Fixed income securities \| Minimum
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	38.00%
Fixed income securities \| Maximum
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	54.00%
Limited partnership interests
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Actual percentage of plan assets	23.00%	21.00%
Limited partnership interests \| Minimum
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	1.00%
Limited partnership interests \| Maximum
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	29.00%
Short-term investments and other
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Actual percentage of plan assets	3.00%	3.00%
Securities Pledged as Collateral
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Fair value of plan assets	$ 180	$ 297