Capitalization of pension and OPEB expense related to engineering and plant construction

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- Definition

Defined Benefit Plan, Settlements Benefit obligation threshold

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- Definition

Percentage of increase in pension plan

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Amount of increase (decrease) in plan assets of defined benefit plan from actual return (loss) determined by change in fair value of plan assets adjusted for contributions, benefit payments, and other expenses.

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Amount of payment to participant of defined benefit plan which decreases benefit obligation. For pension plan, payment includes, but is not limited to, pension benefits and death benefits. For other postretirement plan, payment includes, but is not limited to, prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services.

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- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Amount of contributions received and expected to be received by defined benefit plan from employer in current fiscal year.

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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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Amount of increase (decrease) in plan assets of defined benefit plan.

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Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement.

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Amount of (increase) decrease to benefit obligation of defined benefit plan from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Includes, but is not limited to, lump-sum cash payment to participant in exchange for right to receive specified benefits, purchase of nonparticipating annuity contract and change from remeasurement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Amount of cash outflow for pension benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes other postretirement benefit.

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Retirement Plans (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		7 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jan. 01, 2021	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Capitalization of pension and OPEB expense related to engineering and plant construction	$ 7	$ 6
Defined benefit plan, cash contributions by employer	327
Plan assets	2,166			$ 2,730
Increase in pension assets	$ 564
Percentage of increase in pension plan	21.00%
Positive investment returns	$ 274
Benefit payments	37
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Settlements, Benefit Obligation	310
Defined Benefit Plan, Settlements Benefit obligation threshold	211
Estimated plan contributions	190
Plan contributions	37
Pension settlement costs	$ 103
Forecast [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Plan contributions			$ 153