Pension and Other Postretirement Benefit Plans (Change in Plan Assets) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
Sep. 15, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Employer contribution	$ 358
Other Postretirement Benefits
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of year			$ 0	$ 0
Actual return on plan assets			0	0
Employer contribution			36	40
Plan participants' contributions			0	0
Benefits paid			(36)	(40)
Transfer of plan assets			0	0
Settlements			0	0
Foreign currency exchange rates			0	0
Reclassification of plan assets to held for sale			0	0
Fair value of plan assets, end of year		$ 0	0	0
United States Pension Benefits \| Pension Benefits
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of year			2,746	2,664
Actual return on plan assets			(145)	359
Employer contribution			380	47
Plan participants' contributions			0	0
Benefits paid			(305)	(260)
Transfer of plan assets		64	0	(64)
Settlements			0	0
Foreign currency exchange rates			0	0
Reclassification of plan assets to held for sale			0	0
Fair value of plan assets, end of year		2,746	2,676	2,746
Foreign Pension Benefits \| Pension Benefits
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of year			571	510
Actual return on plan assets			(7)	28
Employer contribution			39	30
Plan participants' contributions			1	1
Benefits paid			(31)	(32)
Transfer of plan assets			0	0
Settlements			(22)	(12)
Foreign currency exchange rates			(31)	46
Reclassification of plan assets to held for sale			(2)	0
Fair value of plan assets, end of year		$ 571	$ 518	$ 571

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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- Definition

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

+ References

No definition available.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

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

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- Definition

Amount of decrease in plan assets of defined benefit plan from disposal or classification as held-for-sale.

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- Definition

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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- Definition

Amount of payment to participant under defined benefit plan which decreases plan assets. 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.

+ References

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- Definition

Amount of contributions received by defined benefit plan from participant which increases plan assets.

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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) plan assets of defined benefit plan.

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- Definition

Amount of payment, which decreases plan assets of defined benefit plan, for irrevocable action relieving primary responsibility for benefit obligation and eliminating risk for obligation and assets used to effect settlement. Transaction constituting settlement includes, but is not limited to, making lump-sum cash payment to participant in exchange for their rights to receive specified benefits and purchasing nonparticipating annuity contract.

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