Benefit Plans - Weighted average assumptions used (Details)	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension benefits
Weighted average assumptions used to determine net pension cost and net postretirement benefit cost
Discount rate	2.84%	3.00%	3.70%
Expected long-term rate of return on plan assets	7.06%	7.08%	7.34%
Cash balance interest credit rate	2.04%	1.65%	2.59%
Weighted average assumptions used to determine benefit obligations
Discount rate	2.93%	2.51%
Cash balance interest credit rate	1.90%	1.65%
Postretirement benefits
Weighted average assumptions used to determine net pension cost and net postretirement benefit cost
Discount rate	2.75%	2.99%	3.61%
Weighted average assumptions used to determine benefit obligations
Discount rate	2.86%	2.39%

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

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- Definition

Weighted-average interest crediting rate used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, cash balance and other defined benefit plans with promised interest crediting rate.

+ References

+ Details

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- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.

+ References

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- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit 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 (k)(3)
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e2919-114920

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- Definition

Weighted-average interest crediting rate used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, cash balance and other defined benefit plans with promised interest crediting rate.

+ References

+ Details

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- References

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- Details

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