Benefit Plans - Changes in Level 3 Plan Assets (Details) - Significant Unobservable Inputs (Level 3) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at January 1	$ 1,057	$ 816
Net Realized and Unrealized Gains/ (Losses)	45	63
Net Purchases, Issuances and Settlements	730	235
Net Transfers Into/(Out of) Level 3	0	0
Currency Impact	70	(57)
Fair value of plan assets at December 31	1,902	1,057
Corporate bonds and other fixed-income securities
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at January 1	1,032	790
Net Realized and Unrealized Gains/ (Losses)	8	62
Net Purchases, Issuances and Settlements	727	236
Net Transfers Into/(Out of) Level 3	0	0
Currency Impact	69	(56)
Fair value of plan assets at December 31	1,836	1,032
Real estate
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at January 1	22	23
Net Realized and Unrealized Gains/ (Losses)	36	1
Net Purchases, Issuances and Settlements	3	(1)
Net Transfers Into/(Out of) Level 3	0	0
Currency Impact	1	(1)
Fair value of plan assets at December 31	62	22
Private equity and other
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Fair value of plan assets at January 1	3	3
Net Realized and Unrealized Gains/ (Losses)	1	0
Net Purchases, Issuances and Settlements	0	0
Net Transfers Into/(Out of) Level 3	0	0
Currency Impact	0	0
Fair value of plan assets at December 31	$ 4	$ 3

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

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.

+ Details

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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
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
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-Publisher FASB
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-Publisher FASB
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-Publisher FASB
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+ Details

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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) plan assets 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 (b)(2)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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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

+ Details

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- Details

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