Retirement Plans - Schedule of Changes in Benefit Obligations and Plan Assets (Details) - Pension Plans, Defined Benefit - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2018
Defined Benefit Plans And Other Postretirement Benefit Plans Table Text Block [Line Items]
Obligation transferred in	$ 6
Benefit obligation at end of the period	6
Funded status recognized in the balance sheet	$ (6)

Amount of actuarial present value of benefits attributed to service rendered by employee for defined benefit plan.

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- Definition

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

+ References

+ Details

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- Definition

Amount of funded (unfunded) status of defined benefit plan, measured as difference between fair value of plan assets and benefit obligation. Includes, but is not limited to, overfunded (underfunded) status.

+ 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 (c)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109237824&loc=d3e1703-114919

+ Details

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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

No definition available.

+ Details

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- Details

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