Employee Benefit Plans - Schedule of Information for Plans with ABOs in Excess of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Projected benefit obligation	$ 1,621	$ 1,692
Accumulated benefit obligation	1,585	1,647
Fair value of plan assets	1,179	1,286
Other Postretirement Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Accumulated benefit obligation	$ 107	$ 187

Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

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-Publisher FASB
-Name Accounting Standards Codification
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Amount of plan asset for defined benefit plan with accumulated benefit obligation in excess of plan assets.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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Amount of projected benefit obligation for defined benefit pension plan with accumulated benefit obligation in excess of plan assets.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
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