Employee Benefit Plans - Health Care Cost Trend Rate (Details)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Retirement Benefits [Abstract]
Defined Benefit Plan Health Care Cost Trend Rate Assumed for Pre Retirement	7.00%	7.00%	6.50%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	4.50%	4.50%	4.50%
Year that the rate reaches the ultimate trend rate	2033	2033	2028

Defined benefit plan health care cost trend rate assumed for pre retirement.

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- References

No definition available.

+ Details

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-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

+ Details

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- Definition

Year ultimate health care cost trend rate is expected to be reached, in CCYY format.

+ References

+ Details

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