Employee Benefit Plans Employee Benefit Plans 6 (Details)	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Employee benefit plans
Actual asset allocations	100.00%	100.00%
Target asset allocations	100.00%
Pension Benefits \| Equity securities
Employee benefit plans
Actual asset allocations	56.00%	53.00%
Target asset allocations	60.00%
Pension Benefits \| Debt securities
Employee benefit plans
Actual asset allocations	39.00%	43.00%
Target asset allocations	40.00%
Pension Benefits \| Real Estate Funds
Employee benefit plans
Actual asset allocations	5.00%	4.00%
Pension Benefits \| Cash equivalents
Employee benefit plans
Actual asset allocations	0.00%	0.00%
Post-Retirement Medical Benefits
Employee benefit plans
Actual asset allocations	100.00%	100.00%
Target asset allocations	100.00%
Post-Retirement Medical Benefits \| Equity securities
Employee benefit plans
Actual asset allocations	61.00%	59.00%
Target asset allocations	60.00%
Post-Retirement Medical Benefits \| Debt securities
Employee benefit plans
Actual asset allocations	38.00%	39.00%
Target asset allocations	40.00%
Post-Retirement Medical Benefits \| Real Estate Funds
Employee benefit plans
Actual asset allocations	0.00%	0.00%
Post-Retirement Medical Benefits \| Cash equivalents
Employee benefit plans
Actual asset allocations	1.00%	2.00%

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=112275985&loc=d3e4179-114921

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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