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 - Weighted average target allocation and actual percentage (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Mutual funds
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	0.00%	3.00%
Pension benefits
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	$ 4,430	$ 6,525	$ 6,987
Pension benefits \| Equity securities
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Actual percentage of plan assets	27.00%	55.00%
Pension benefits \| Equity securities \| Minimum
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	22.00%
Pension benefits \| Equity securities \| Maximum
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	36.00%
Pension benefits \| Fixed income securities
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Actual percentage of plan assets	49.00%	30.00%
Pension benefits \| Fixed income securities \| Minimum
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	43.00%
Pension benefits \| 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%
Pension benefits \| Limited partnership interests
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Actual percentage of plan assets	21.00%	14.00%
Pension benefits \| 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%
Pension benefits \| Limited partnership interests \| Maximum
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	24.00%
Pension benefits \| Short-term investments and other
Pension plans' weighted average target percentage of plan assets and the actual percentage of plan assets
Target asset allocation	0.00%
Actual percentage of plan assets	3.00%	1.00%
Pension benefits \| 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	$ 297	$ 121