Employee Benefit Plans - Plan Asset Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Pension Plans Defined Benefit [Member] \| U.S.
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 2,161	$ 1,969
Defined Benefit Plan, Actual Return on Plan Assets	273	(112)
Insurance Contract Rights And Obligations Fair Value Option [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Participating Interest In Annuity Contract	95	84
Insurance Contract Rights And Obligations Fair Value Option [Member] \| Fair Value, Inputs, Level 3 [Member] \| Pension Plans Defined Benefit [Member] \| U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Participating Interest In Annuity Contract	95	84
Accumulated benefit obligation	140	144
Defined Benefit Plan, Actual Return on Plan Assets	(4)
Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease)	$ 7
Defined Benefit Plan, Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for plan assets	37.00%
Defined Benefit Plan, Debt Security [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for plan assets	56.00%
Defined Benefit Plan, Debt Security [Member] \| Insurance Contract Rights And Obligations Fair Value Option [Member] \| Fair Value, Inputs, Level 3 [Member] \| Pension Plans Defined Benefit [Member] \| U.S.
Defined Benefit Plan Disclosure [Line Items]
Fair Value Of Participating Interest In Annuity Contract	$ 235	$ 228
Defined Benefit Plan, Real Estate [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for plan assets	6.00%
Other Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Target allocations for plan assets	1.00%

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- Definition

Amount of actuarial present value of benefits attributed to employee service rendered, excluding assumptions about future compensation level.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
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- Definition

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.

+ 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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Amount of increase (decrease) in benefit obligation of defined benefit plan.

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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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Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

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-Publisher FASB
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