Retirement Benefits (Schedule of Fair Value Measurement of Plan Assets Using Significant Unobservable Inputs) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Change in plan assets:
Fair value of plan assets at beginning of period	$ 1,572
Fair value of plan assets at end of period	1,787	$ 1,572
Level 3
Change in plan assets:
Fair value of plan assets at beginning of period	126
Fair value of plan assets at end of period	149	126
Int’l
Change in plan assets:
Fair value of plan assets at beginning of period	1,518	1,673
Foreign exchange impact	46	(114)
Fair value of plan assets at end of period	1,727	1,518
Int’l \| Level 3
Change in plan assets:
Fair value of plan assets at beginning of period	126	74
Return on assets held at end of year	8	(3)
Return on assets sold during the year	1	8
Purchases, sales and settlements	11	39
Transfers	0	13
Foreign exchange impact	3	(5)
Fair value of plan assets at end of period	149	126
Int’l \| Equities
Change in plan assets:
Fair value of plan assets at beginning of period	84
Fair value of plan assets at end of period	103	84
Int’l \| Equities \| Level 3
Change in plan assets:
Fair value of plan assets at beginning of period	84	26
Return on assets held at end of year	10	1
Return on assets sold during the year	0	0
Purchases, sales and settlements	7	11
Transfers	0	48
Foreign exchange impact	2	(2)
Fair value of plan assets at end of period	103	84
Int’l \| Fixed Income
Change in plan assets:
Fair value of plan assets at beginning of period	2
Fair value of plan assets at end of period	1	2
Int’l \| Fixed Income \| Level 3
Change in plan assets:
Fair value of plan assets at beginning of period	2	5
Return on assets held at end of year	0	0
Return on assets sold during the year	0	0
Purchases, sales and settlements	(1)	(3)
Transfers	0	0
Foreign exchange impact	0	0
Fair value of plan assets at end of period	1	2
Int’l \| Real Estate
Change in plan assets:
Fair value of plan assets at beginning of period	1
Fair value of plan assets at end of period	2	1
Int’l \| Real Estate \| Level 3
Change in plan assets:
Fair value of plan assets at beginning of period	1	3
Return on assets held at end of year	0	(1)
Return on assets sold during the year	1	1
Purchases, sales and settlements	0	(2)
Transfers	0	0
Foreign exchange impact	0	0
Fair value of plan assets at end of period	2	1
Int’l \| Other
Change in plan assets:
Fair value of plan assets at beginning of period	74
Fair value of plan assets at end of period	87	74
Int’l \| Other \| Level 3
Change in plan assets:
Fair value of plan assets at beginning of period	39	40
Return on assets held at end of year	(2)	(3)
Return on assets sold during the year	0	7
Purchases, sales and settlements	5	33
Transfers	0	(35)
Foreign exchange impact	1	(3)
Fair value of plan assets at end of period	$ 43	$ 39

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets sold.

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan from actual return (loss) on assets still held.

+ References

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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 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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)(5)
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- Definition

Amount, measured using unobservable input, of increase (decrease) in plan asset of defined benefit plan from purchase, sale and settlement of trade associated with underlying investment.

+ References

+ Details

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- Definition

Amount, measured using unobservable inputs, of increase (decrease) in plan assets of defined benefit plan, for assets transferred into (out of) Level 3 of fair value hierarchy. Includes, but is not limited to, transfer due to change in observability of significant inputs.

+ References

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