Pension and Other Postretirement Benefits - Assumed health care trend rates (Details)	Dec. 31, 2019
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Medical cost inflation, years 13 and thereafter	4.50%
Pre 65 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Medical cost inflation rate	6.40%
Post 65 [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Medical cost inflation rate	7.05%

Assumed rate, for next fiscal year, based on annual change in cost of health care cost benefits used to measure expected cost of benefits covered by defined benefit postretirement plan. Factors include, but are not limited to, estimate of health care inflation, change in health care utilization or delivery pattern, technological advances, and change in health status of participant. Excludes factors for change in composition of plan population by age and dependency status.

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 (l)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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- Definition

Ultimate trend rate for health care cost for defined benefit postretirement plan.

+ References

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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.

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