Employee Benefits - Asset Target Allocations Prescribed by Trusts' Investment Policies (Details)	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	100.00%
Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	100.00%
Equity securities \| Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	80.00%
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	84.00%
Fixed income securities \| Other Postretirement Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Target Allocation	20.00%

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.

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=123450688&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=123447040&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanPlanAssetsTargetAllocationPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant