Employee Pension and Other Postretirement Benefits Schedule of Defined Benefit Plans Disclosures, Cash Contributions (Table) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plan Disclosure [Line Items]
Other benefit plans	$ 30	$ 34	$ 32
Total contributions	546	335	205
Discretionary Contribution [Member] \| Qualified [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension contributions	508	294	167
Discretionary Contribution [Member] \| Non-qualified [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension contributions	$ 8	$ 7	$ 6

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Amount of cash outflow for other postretirement benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes pension benefit.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3536-108585

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Amount of cash outflow for pension and other postretirement benefits. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree.

+ References

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Amount of cash outflow for pension benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes other postretirement benefit.

+ References

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