Retirement Benefits (Schedule of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
United States
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial loss, net of tax of $9 and $215, $10 and $203, respectively	$ 22	$ 23
Total in accumulated other comprehensive loss	22	23
Unrecognized actuarial loss, tax	(9)	(10)
Int’l
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial loss, net of tax of $9 and $215, $10 and $203, respectively	632	569
Total in accumulated other comprehensive loss	632	569
Unrecognized actuarial loss, tax	$ (215)	$ (203)

Defined Benefit Plan, Benefit Obligation, Unrecognized Actuarial Gain (Loss), Tax

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- Definition

Amount, after tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669686-108580

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- Definition

Amount, after tax, of accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 14A
-URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669686-108580

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-Publisher FASB
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-Section 50
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- Definition

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.

+ References

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